Interview Questions and Answers are now updated with SQL Server 2008 Questions and its answers.
SQL SERVER – Index Seek Vs. Index Scan (Table Scan)
Index Scan retrieves all the rows from the table. Index Seek retrieves selective rows from the table.
SQL SERVER – Difference between DISTINCT and GROUP BY – Distinct vs Group By
This question is asked many times to me. What is difference between DISTINCT and GROUP BY? A DISTINCT and GROUP BY usually generate the same query plan, so performance should be the same across both query constructs. GROUP BY should be used to apply aggregate operators to each group. If…
Read MoreSQL SERVER – SQL Commandments – Suggestions, Tips, Tricks
Few days ago, while searching for something on web site, I came across a very good article of 25 SQL Commandments. I really enjoyed reading it. It was for Oracle, I re-wrote it for SQL Server. First 18 points are taken from original article and last 2 I added to…
Read MoreSQL SERVER – SQL Server 2005 Samples and Sample Databases (February 2007)
The samples download provides over 100 samples for SQL Server 2005, demonstrating the following components: Database Engine, including administration, data access, Full-Text Search, Common Language Runtime (CLR) integration, Server Management Objects (SMO), Service Broker, and XML Analysis Services Integration Services Notification Services Reporting Services Replication The samples databases downloads include…
Read MoreSQL SERVER – FIX : Error 15023: User already exists in current database.
Error 15023: User already exists in current database. 1) This is the best Solution. First of all run following T-SQL Query in Query Analyzer. This will return all the existing users in database in result pan. USE YourDB GO EXEC sp_change_users_login 'Report' GO Run following T-SQL Query in Query Analyzer…
Read MoreSQL SERVER – Primary Key Constraints and Unique Key Constraints
Primary Key: Primary Key enforces uniqueness of the column on which they are defined. Primary Key creates a clustered index on the column. Primary Key does not allow Nulls. Create table with Primary Key: CREATE TABLE Authors ( AuthorID INT NOT NULL PRIMARY KEY, Name VARCHAR(100) NOT NULL ) GO…
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