SQL SERVER – Tips from the SQL Joes 2 Pros Development Series – Advanced Aggregates with the Over Clause – Day 11 of 35

Answer simple quiz at the end of the blog post and -
Every day one winner from India will get Joes 2 Pros Volume 2.
Every day one winner from United States will get Joes 2 Pros Volume 2.

Partitioning with the Over Clause (Part 2)

Yesterday we learned how the over clause can be used to compare your number against the overall aggregated number for an entire result set. Sometimes you might want your number to be compared against its category and not all records from a table. For example I don’t get any joy in saying I never won the state championship in Greco Roman wrestling. On the other hand with great joy I tell people was the Tacoma City Champion. By partitioning the sport down into City instead of the entire country or state my ranking is much better.

Businesses might have other reasons for partitioning a group. Let’s use an example of schools where they see most of them getting a drop in attendance during the summer time. Comparing an attendance trend from spring to summer would not show an uptrend even if your school is growing year after year. It makes more sense to compare this summer to last summer to find a trend then to compare the spring and summer where you always see a drop. Whatever your reason you can get a total by a level of your choosing with the OVER() clause. Now let’s try an example using the aggregate function COUNT( ) with the OVER( ) clause. We’ll start with a simple query on the Employee table. Here we see Alex Adams is just 1 employee out of 13.  In fact each employee is one of 13 in this example.

Now let’s look at Alex Adams. He works in Location 1. How many of JProCo’s employees are in Location 1 (Seattle)? And how many of the total employees work in Boston? Alongside the existing table records, we want to add a column showing the count of employees at each location. Recall that blank parentheses cause OVER( ) to apply the aggregation across all rows of a query. Our instruction to show employee count at each location means we don’t just want a total of all locations in our query – we already have that data displayed in the TotalEmployees column. We must include an argument inside the parentheses. PARTITION BY divides the result set into partitions. In this case we’ve added a partition by LocationID.

Similar to the behavior of GROUP BY, the command to PARTITION BY LocationID takes the LocationID for each employee and counts the number of records in that group which shares the same LocationID. Thus, each of the Seattle employees shows a 7 for LocationCount. The Boston employees have a LocationCount of 3, and the Spokane records have LocationCount of 2. John Marshbank shows LocationCount of 1, since he’s the only one with a null LocationID.

Since Seattle has 7 of the total 13 employees, we can guesstimate that just over ½ (or more than 50%) of JProCo employees work in Seattle (LocationID 1). Let’s run the query and check the results.

Our result set shows no ratios and all 0’s. This is because our calculation involved only integers. (The grant amount data was expressed in decimal form.) Rather than writing additional code using CAST, we’ll use a trick that works with many programming languages. Multiply the numerator by 1.0 to make each figure display as a decimal instead of an integer. Multiply the numerator by 1.0, so results appear as decimals instead of integers.

This result is a big improvement – each result is now in decimal form. The Seattle occupancy rate is about 53.85%.  Now multiply instead by 100 so the values show as percentages, like we did with the Grant example. In this instance be sure to multiply by 100.0, so the values show as decimals and not integers. 

Finally, polish your report by adding the descriptive title Pct in place of the blank column header. Sort your report in descending order of occupancy (Pct) and LastName.

Note: If you want to setup the sample JProCo database on your system you can watch this video. For this post you will want to run the SQLQueriesChapter5.0Setup.sql script from Volume 2.

Question 11

Q 11) You have a table named CurrentProducts. The table contains a column named Category. You need to make a T-SQL statement that calculates the percentage (with decimals) of products in each product Category. Which query should you use?

  1. SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts
  2. SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts
  3. SELECT DISTINCT Category,
    COUNT(*) OVER ( )*100.0/ COUNT(*) OVER(PARTITION BY Category) as PctCategory
    FROM CurrentProducts

Rules:

Please leave your answer in comment section below with correct option, explanation and your country of resident.
Every day one winner will be announced from United States.
Every day one winner will be announced from India.
A valid answer must contain country of residence of answerer.
Please check my facebook page for winners name and correct answer.
Winner from United States will get Joes 2 Pros Volume 2.
Winner from India will get Joes 2 Pros Volume 2.
The contest is open till next blog post shows up at http://blog.sqlauthority.com which is next day GTM+2.5.

Reference:  Pinal Dave (http://blog.SQLAuthority.com)

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112 thoughts on “SQL SERVER – Tips from the SQL Joes 2 Pros Development Series – Advanced Aggregates with the Over Clause – Day 11 of 35

  1. Correct answer is option #2.

    2.SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    – as expained clearly in the aritcle above.

    Option #1 displays categories with percentages in integer values.
    Option #2 displays categories with percentages in decimal values.
    Option #3 displays incorrect results.

    Thanks.

    Country – India

    Like

  2. Correct answer is No. 2, because the OVER() includes a PARTITION BY clause and uses a multiplication by 100.0 to show results as percentage.
    Rene Castro
    El Salvador

    Like

  3. Hi

    The answer is option 2
    Reason we are counting for each category * 100.0 for making the result to float and / count * to divide by total count we will get category wise percentage for each category
    Sathya – India

    Like

  4. Option 2 is correct because we need to partition by Category and have result in decimal places so 100.0 must be used.

    Thanks

    Sudhir Chawla
    New delhi, India

    Like

  5. Question 11

    Q 11) You have a table named CurrentProducts. The table contains a column named Category. You need to make a T-SQL statement that calculates the percentage (with decimals) of products in each product Category. Which query should you use?

    Answer is :2 Gives the result in decimal with correct results
    2. SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Wrong :As we expecting resulst in decimal, following query wont give results in decimal
    1. SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Wrong:Before dividing we are using COUNT(*) OVER ( )*100.0–>this will takes the total count of all rows as over clause is not partitioned and
    COUNT(*) OVER(PARTITION BY Category) —>divider will be less as we have specified the PARTITION BY Category for count ..This will give invalid result.
    3. SELECT DISTINCT Category,
    COUNT(*) OVER ( )*100.0/ COUNT(*) OVER(PARTITION BY Category) as PctCategory
    FROM CurrentProducts

    Thanks for the post :-)

    Country: India

    Like

  6. Option 2:
    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Option 1 has results in integer without the decimals

    Option 3 is wrong as it has total product count in the numerator

    Leo PIus
    USA

    Like

  7. Correct answer is option 2

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Sumit

    India

    Like

  8. Pingback: SQL SERVER – Win a Book a Day – Contest Rules – Day 0 of 35 Journey to SQLAuthority

  9. Ans is 2 option
    2.SELECT DISTINCT Category,
    COUNT(*) OVER ( )*100.0/ COUNT(*) OVER(PARTITION BY Category) as PctCategory
    FROM CurrentProducts

    Partha
    India

    Like

  10. Option 2 is correct.

    2.SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    As Option 1 is nearly correct but it will return value in integer.
    Option 3 is incorrect any how.

    INDIA

    Like

  11. Correct answer is option 2 that is

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Because we need to display percentage (with decimals) of products in each product Category we need first to find two things
    1. No of product in particular category
    2. Total no of products in the table
    and also we need result in decimal point we have to use COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() .

    Mahmad Khoja
    INDIA
    AHMEDABAD

    Like

  12. The answer to this question is 2nd option.

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Option 1: Gives the Percentage of products since it is partitioned by Category without the decimals over the total count.
    Option 2: Gives the Percentage of products since it is partitioned by Category with the decimals over the total count.
    Option 3:This query doesn’t give the percentage but gives the value of total count over count per category.

    Nagaraj Ejanthkar
    USA

    Like

  13. Option 2 is correct answer as

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    because it displays categories with percentages in decimal values.

    Varinder Sandhu (India)

    Like

  14. Answer No. 2 is correct

    The OVER() includes a PARTITION BY clause with Category which count the records category wise and uses a multiplication by 100.0 and division by all records of the table to show results as percentage.

    India

    Like

  15. Answer is :

    SELECT DISTINCT Category,
    COUNT(*) OVER ( )*100.0/ COUNT(*) OVER(PARTITION BY Category) as PctCategory
    FROM CurrentProducts

    Like

  16. Answer is 2:

    SELECT DISTINCT Category,
    COUNT(*) OVER ( )*100.0/ COUNT(*) OVER(PARTITION BY Category) as PctCategory
    FROM CurrentProducts

    because: Answer 1 will give integer value,
    answer 2 will give exact decimal points…

    Chennai
    India

    Like

  17. Answer is 2:

    SELECT DISTINCT Category,
    COUNT(*) OVER ( )*100.0/ COUNT(*) OVER(PARTITION BY Category) as PctCategory
    FROM CurrentProducts

    because: Answer 1 is giving integer,
    answer 2 will give exact decimal points…

    Chennai
    India

    Like

  18. Answer for today blog quiz : Option 2

    2) SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Chennai, TamilNadu, India

    Like

  19. 1st option gives only number eg: 20
    3rd option gives in decimal but wrong answer eg:500.000000000000
    2nd option is correct…it gives 20.000000000000

    2.SELECT DISTINCT Category,
    COUNT(*) OVER ( )*100.0/ COUNT(*) OVER(PARTITION BY Category) as PctCategory
    FROM CurrentProducts

    Arjun

    India

    Like

  20. Answer : Option 2

    2) SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Chennai, TamilNadu, India

    Like

  21. Correct Answer is: B
    Because This Query only have proper syntax and multiple by 100.0 not 100. So we will get the Percentage with Decimal values.

    by GVPrabu || INDIA ||

    Like

  22. Hi,

    Q: You have a table named CurrentProducts. The table contains a column named Category. You need to make a T-SQL statement that calculates the percentage (with decimals) of products in each product Category. Which query should you use?

    2) SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Thanks pinal, I learn New Thing from Last To Day …..

    I am from India….

    Like

  23. Hi Sir,

    Option no 2 is the correct answer as this will give the percentage of products in each product category with decimals

    2. SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    option no 1 also give the result but with out decimals

    1. SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    option no 3 will provide invalid result as the numerator and denominator are interchanged.

    3. SELECT DISTINCT Category,
    COUNT(*) OVER ( )*100.0/ COUNT(*) OVER(PARTITION BY Category) as PctCategory
    FROM CurrentProducts

    So the correct answer is option no 2.

    P.Anish Shenoy
    INDIA,Bangalore, Karnataka

    Like

  24. The elimination method:

    Q:: You need to make a T-SQL statement that calculates the percentage (with decimals) of products in each product Category.

    1… (with decimals) >> Eliminates 1st query.
    2… products in each product Category. >> Eliminates 3rd query.

    So, #2 has to be right and it is.

    Like

  25. The elimination method:

    Q:: You need to make a T-SQL statement that calculates the percentage (with decimals) of products in each product Category.

    1… (with decimals) >> Eliminates 1st query.
    2… products in each product Category. >> Eliminates 3rd query.

    So, #2 has to be right and it is.

    Kedar (India)

    Like

  26. Correct Answer is 2

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Rajesh Garg
    India

    Like

  27. Hi,

    Correct answer is 2

    We have to use “100.0”, so it will give us result with Decimals (Accurate)
    Option 1: will give us result in INT, so its not that much accurate

    COUNTRY: INDIA

    Like

  28. Answer 2 is correct:

    2.SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    City: Baroda
    Country: India

    Thanks,
    GurjitSingh

    Like

  29. Option 2 is correct answer as

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    because it displays categories with percentages in decimal values.

    Explaniation:

    1.First and second query are same there is only difference we are multiple with decimal value in second query that why! second query is returning in decimal. here //T-SQL statement that calculates the percentage (with decimals) of products in each product Category.// for each products we are getting decimal values
    In SQL Server, The result is decimal when either of the following is true:
    # Both expressions are decimal.
    # One expression is decimal and the other is a data type with a lower precedence than decimal.
    so here count is integer value and percentage [100.0] is contains decimal.

    2. third query returns count of all rows as over clause and calculating but as per your question here we need //T-SQL statement that calculates the percentage (with decimals) of products in each product Category.// so third query is wrong..

    Thanks,

    Vijayakumar P Kochi (India)

    Like

  30. 2nd option is correct:

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    City: Baroda
    Country: India

    Like

  31. The Correct Answer is : 2

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Mohd Thoufeek
    India
    Chennai

    Like

  32. The correct Option is 2.

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    India

    Like

  33. Correct Answer is Option 2

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Explanation: Option 1 provides the percentage of products in each product Category but not with decimals as there is not a single expression in decimals so result will be in integers only. In option 2 count of each type of category is divided by total count of products ad as it is multiplied by a expression having decimal points, the result will be with decimals.
    and Option 3 will produce wrong result as it divides count of all products with count of each type of product.

    Country – INDIA (Gujarat)

    Like

  34. 2.SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Like

  35. Hello!

    Option 2 will get the desired result.

    Option 1 will suffer from calculating only with integers.
    Option 3 does not use the “partition by” clause for the first over clause. Thus leads to wrong results since it will calculate always with all categories.

    Best wishes,

    Michael Mikic
    from Germany

    Like

  36. Correct Answer: option 2.

    1. SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts
    – This query involved only integers. So the result set shows no ratios and all 0’s.

    2. SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts
    – This query writes additional code using CAST. Multiply the numerator by 1.0 to make each figure display as a decimal instead of an integer.

    3. SELECT DISTINCT Category,
    COUNT(*) OVER ( )*100.0/ COUNT(*) OVER(PARTITION BY Category) as PctCategory
    FROM CurrentProducts
    – This query writes additional code using CAST. But the calculation is wrong.

    Like

  37. Correct answer is #2.SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Country: India

    Like

  38. Ans is 2 option
    2.SELECT DISTINCT Category,
    COUNT(*) OVER ( )*100.0/ COUNT(*) OVER(PARTITION BY Category) as PctCategory
    FROM CurrentProducts

    Pritesh Mehta
    India

    Like

  39. Correct Answer is

    2.SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Country: India.

    Like

  40. Correct answer is option 2.

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Karan,
    India

    Like

  41. Option 2 :-
    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Somnath Desai

    India

    Like

  42. Option 2 is correct:

    [It will return results with decimal points.]

    2.SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Option 1 will return values without perc therefore wrong.
    Option 3 will result incorrect data therefore wrong again.

    Thanks
    Vivek Srivastava

    Country: India

    Like

  43. The answer is #2

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Basically #1 will return an int, not a decimal and #3 is not the correct calculation for returning the percentage we want. To get a percent of each subset (categorey) we’d want the subset over the entire set, not the reverse.

    Deb – USA

    Like

  44. Correct Answer : 2

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Shekhar Gurav.
    Country : INDIA

    Like

  45. In order to achieve the desired results, the second option would be the correct SQL query to use:

    2.SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Country: United States

    Like

  46. The correct answer is #2

    #1 has *100 and should be *100.0 to get decimals and
    #3 has the overall count in the numerator and the Category count in the denominator which is backwards.

    USA

    Mike Michalicek

    Like

  47. Option : 2 is correct.

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    This query will gives the decimal values.
    ————
    Option :1 (Wrong) this query will return only integer values
    Option :2 (Wrong) this query will return without percentage but gives the value of total count over count per category

    Thanks,
    Rajasekar.k
    Bangalore- INDIA

    Like

  48. Option : 2 is correct.

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    This query will gives the decimal values.
    ————
    Option :1 (Wrong) this query will return only integer values
    Option :3 (Wrong) this query will return without percentage but gives the value of total count over count per category

    Thanks,
    Rajasekar.k
    Bangalore- INDIA

    Like

  49. SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Chetan – USA

    Like

  50. Here is how I would make a T-SQL statement that calculates the percentage (with decimals) of products in each product Category.

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    The answer is option 2.

    David
    USA

    Like

  51. Answer for today blog quiz : Option 2

    2) SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Chennai, TamilNadu, India

    Like

  52. I will use the option #2. Option #1 and Option #2 are almost the same except for multiplier of 100.0 vs. 100 in the first case. Using 100.0 we implicitly tell SQL Server to use decimals and not integer math. In SQL Server (and in some other languages) when you divide one integer by another integer you get an integer as a result. So, that’s why the option #1 is not correct.

    Option #3 has the calculation backwards.

    I am from USA

    Like

  53. The correct option is 2

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Option 1 is incorrect because it doesn’t multiply by 1.0 to get the answer in decimal.

    Option 3 is incorrect because it divides the total products by the number of products in the category. This is not the correct calculation.

    Option 2 is correct because it divides the number of products in the categury by the dotal number of products, and uses the *100.0 to ensure that the answer comes out as decimal.

    Country of Residence: USA

    Like

  54. Correct answer for the above question is 2 option

    Option 2) SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Explaining the reason :

    As the Requirement is we need to display percentage (with decimals) of products in each product Category needing first to find two things
    A. No of product in particular category
    B. Total no of products in the table
    and the requirement is that we need the result in decimal point so we have to use COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as clearly explained by you.

    Diljeet kumari
    INDIA

    Like

  55. Hi Pinal,

    Challenge:
    Q 11) You have a table named CurrentProducts. The table contains a column named Category. You need to make a T-SQL statement that calculates the percentage (with decimals) of products in each product Category. Which query should you use?

    1.SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts
    2.SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts
    3.SELECT DISTINCT Category,
    COUNT(*) OVER ( )*100.0/ COUNT(*) OVER(PARTITION BY Category) as PctCategory
    FROM CurrentProducts

    Correct Answer:
    The correct answer is #2:
    SELECT DISTINCT Category, COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Explanation:
    Items #1 will not give you the resultant PctCategory in decimals since you are dividing with an integer.

    Item #3 is giving you the percentage that is greater than 100%.

    The correct answer is #2.

    Country:
    United States

    Thanks for the knowledge!

    Regards,

    Bill Pepping

    Like

  56. Answer is Option #2….we have to use 100.0 in order to get decimals, so option #1 is out, and Option #3 does not give what we want either.

    Thomas Riehle
    USA

    Like

  57. 2) SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Chennai, TamilNadu, India

    Like

  58. Correct ans is 2.
    2.SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    India

    Like

  59. Answer ::—>

    1. SELECT DISTINCT Category, COUNT(*) OVER (PARTITION BY Category)*100/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts
    –This option will be incorrect because,statement will calculate percentage without decimal.

    2.SELECT DISTINCT Category, COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts
    –This is correct option.

    3.SELECT DISTINCT Category, COUNT(*) OVER ( )*100.0/ COUNT(*) OVER(PARTITION BY Category) as PctCategory
    FROM CurrentProducts
    –In this case formula to calculate percentage is incorrect so, this option will generate wrong result. So this is incorrect option.

    County- India

    -Dnyanesh

    Like

  60. 2.SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Gordon Kane
    Allen TX
    USA

    Like

  61. The correct answer is option 2
    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    because option 1 show result wih no decimals, and option 3 whow wrong information

    Leonardo

    From: Chile

    Like

  62. Hi Pinal Sir,

    The answer for the above question is Option no 2 is the correct Option as this calculates the percentage (with decimals) of products in each product Category with decimals

    2. SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Option 1) This gives us the results products in each product Category but with out decimals

    Option 3)This option provide invalid result as the numerator and denominator are reversed and will not fetch the result.

    So the option left and which gives us the result is is option no 2.

    DILIP KUMAR JENA
    Country : INDIA

    Like

  63. SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    To calculate the percentage (with decimals) of products in each product Category.

    Like

  64. Option 2:
    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Option 1 -> has results in integer without the decimals

    Option 3 -> is wrong as it has total product count in the numerator

    country : USA

    Like

  65. Hi Pinal,

    I checked your Facebook link and I didn’t find the winner for this post mentioned explicitly. Its the same page as this one.

    Am I missing something ?

    Thanks

    Like

  66. Q 11) SQL SERVER – Tips from the SQL Joes 2 Pros Development Series – Advanced Aggregates with the Over
    Clause – Day 11 of 35

    A.) Because multiplying an aggregate by 100 (an integer) will result in the nearest integer (1) will not work. Since alculating a category’s percentage of the total products is done by dividing the quantity in the category by the quantity of all the products then multiplying by 100.0 (3) will be incorrect because it is dividing the total (COUNT(*) OVER ( )) by the category (COUNT(*) OVER(PARTITION BY Category)) instead. Because the category’s quantity is being multiplied by 100.0 (a decimal) before being divided by the quantity of all the products it will result in a decimal making (2) the correct answer.

    Winner from USA: Nagaraj Ejanthkar

    Winner from India: P.Anish Shenoy

    I thank you all for participating here. The permanent record of this update is posted on facebook page.

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  67. Correct answer is answer 2 ie..

    2.SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    because

    Option no 1–> displays categories with percentages in integer values.
    Option no2 –> displays categories with percentages in decimal values.
    Option no 3 –> displays incorrect results.

    India

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  68. Correct Answer 2

    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Wrong Answer 1 : your are meansed Percentage with decimals, this query division value integer and count result value also integer , so result should be integer
    Wrong Answer 3: this query it will provide invalid result set as the numerator and denominator are interchanged.

    Sivaguru.u
    India

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  69. Answer is #2:
    SELECT DISTINCT Category,
    COUNT(*) OVER (PARTITION BY Category)*100.0/ COUNT(*) OVER() as PctCategory
    FROM CurrentProducts

    Thanks,
    Wayne (USA)

    Like

  70. Pingback: SQL SERVER – SQL Query Techniques For Microsoft SQL Server 2008 – Book Available for SQL Server Certification Journey to SQLAuthority

  71. Dear Pinal,

    I think you have the wrong picture before this text : “Our result set shows no ratios and all 0’s.”

    Thank you for all the extremely useful content.

    Cheers, Spyros

    Like

  72. Pingback: SQL SERVER – Identity Fields – Contest Win Joes 2 Pros Combo (USD 198) – Day 2 of 5 « SQL Server Journey with SQL Authority

  73. Pingback: SQL SERVER – Weekly Series – Memory Lane – #042 | Journey to SQL Authority with Pinal Dave

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