UNION removes duplicate rows like SELECT DISTINCT, while UNION ALL keeps them all. My early notes on Union vs. Union All, with a link to the rewritten post.
SQL SERVER – SQL Server 2005 Samples and Sample Databases (February 2007)
SQL Server 2005 Samples gave learners AdventureWorks and the smaller AdventureWorksLT. Why they mattered and where to find sample databases today.
SQL SERVER – FIX : Error 15023: User already exists in current database.
Error 15023: User already exists in current database. I fix it with sp_change_users_login, using Report, Auto_Fix or Update_One to link the user to a login.
SQL SERVER – Primary Key Constraints and Unique Key Constraints
Primary Key and Unique Key both enforce uniqueness, but they differ in the index they create and in NULL handling. Here are the differences and the scripts.
SQL SERVER – ReIndexing Database Tables and Update Statistics on Tables
ReIndexing Database tables with DBCC DBREINDEX and sp_MSforeachtable, then sp_updatestats to refresh statistics. Two scripts, including the one I prefer.
SQL SERVER – Shrinking Truncate Log File – Log Full
The old code I used to truncate log file space with DBCC SHRINKFILE and BACKUP LOG WITH TRUNCATE_ONLY. It breaks the log chain, so take a full backup after.