LEFT JOIN or NOT IN: which one gives Join Better Performance? It depends on the data. Compare the two queries and their execution plans on AdventureWorks.
EOMONTH: Month Ends Are Different From DATEADD Month Clipping
EOMONTH gives me a month-end date when that is the actual reporting requirement. DATEADD moves a date by a month. These operations can agree for one step and disagree on the next.
SQL SERVER – 2008 – Row Constructors – Load Temp Tables From Stored Procedures
Load temp tables from stored procedures with a simple INSERT INTO EXEC instead of a loopback OPENQUERY. Here is the before and after code.
TAN: Keep the Angle Away From Its Undefined Point
TAN reads radians and returns float. These safe angles demonstrate sign and magnitude while explaining why a large finite float near ninety degrees is not a meaningful infinity.
PATINDEX and CHARINDEX: Pattern or Literal Search
PATINDEX and CHARINDEX answer different questions. Compare wildcard patterns with literal searches, preserve NULL, and pin collation for digit ranges.
SQL SERVER – 2005 – Find Database Collation Using T-SQL and SSMS – Part 2
Reader jwwishart shared another way to find database collation in SQL Server 2005: a one line SELECT of collation_name from sys.databases.
SQL SERVER – 2005 – Restore Database Using Corrupt Datafiles (.mdf and .ldf) – Part 2
A last resort for corrupt datafiles with no backup: emergency mode, single user, then DBCC CHECKDB with repair_allow_data_loss. Back up the files first.