Union Archives - SQL Authority with Pinal Dave

Interview Question of the Week #017 – Performance Comparison of Union vs Union All

April 26, 2015

SQL, SQL Interview Questions and Answers, SQL Server, SQL Tips and Tricks

Here is what I just learned from email. One of the very prestigious organization asks one of their candidate following questions – Question: If you have options to use Union or Union All – which one of the option will use keeping performance as a top most requirement for the query. Answer: Though…

SQL SERVER – Simple Puzzle with UNION – Part 5

September 11, 2013

Pinal Dave

SQL, SQL Server, SQL Tips and Tricks

SQL Scripts, SQL Union clause, Union

It seems that my yesterday’s Simple Puzzle with UNION intrigued many readers. Here is my fifth and final part of this Puzzles with UNION. I strongly suggest to read yesterday’s puzzle before continuing today’s puzzle as it is very much based on yesterday’s puzzle. SQL SERVER – Simple Puzzle with UNION…

SQL SERVER – Simple Puzzle with UNION – Part 4

September 10, 2013

Pinal Dave

SQL, SQL Server, SQL Tips and Tricks

SQL Union clause, Union

When I started to write Simple Puzzle with UNION last week, I had no clue this will be extremely popular blog post and will turn into a mini-series. Earlier I wrote three different blog posts on this subject and they are very well received. All the three blog posts which…

SQL SERVER – Simple Puzzle with UNION – Part 3

September 9, 2013

Pinal Dave

SQL, SQL Server, SQL Tips and Tricks

SQL Union clause, Union

Earlier last week I had two simple puzzles related to UNION clause and the response to those puzzles have been amazing. Lots of email I have received that people wants me to post such basics puzzle again. Well here is one more puzzle which uses UNION and tests your basic…

SQL SERVER – Simple Puzzle with UNION – Part 2

September 6, 2013

Pinal Dave

SQL, SQL Puzzle, SQL Server, SQL Tips and Tricks

SQL Union clause, Union

Yesterday we had very easy kind of Back to Basics Puzzle with UNION and I have received tremendous response to the simple puzzle. Even though there is no giveaway due to sheer interest in the subject, I have received many replies. Due to all the request, here is another back…

SQL SERVER – Simple Puzzle with UNION

September 5, 2013

Pinal Dave

SQL, SQL Puzzle, SQL Server, SQL Tips and Tricks

SQL Scripts, SQL Union clause, Union

It has been a long time since played a simple game on SQLAuthority.com. Let us play a simple game today. It is very simple puzzle but indeed a fun one. First let us execute following SQL. Query 1: SELECT 1 UNION ALL SELECT 1 ORDER BY 1 It will return…

SQL SERVER – UNION ALL and UNION are Different Operation

April 26, 2013

Pinal Dave

SQL Tips and Tricks

SQL Scripts, SQL Server, SQL Union clause, Union

I have previously written about the difference between UNION ALL and UNION multiple times over this blog but it seems like this question never gets old and I keep on getting the question again and again. Let us learn about the different operations about the unions.