rohit11.jagannath (4/24/2013)
2) Removal of unused variables
Code cleanup, not much to do with optimisation
4) Replacement of multiple 'Set' statements with a single select statement.
That's more a style decision than anything else in most cases.
5) Removing unnecessary BEGIN or END
Code cleanup, not much to do with optimisation
7) Replacing 'Else If' conditional blocks with 'Case' statement blocks
SQL doesn't have a CASE that can replace if/else blocks. SQL's case is a part of a select/insert/update/delete statement
Take a read through this, yes, it's SQL 2008, most of the principals apply.
http://www.amazon.com/Server-Performance-Tuning-Distilled-Experts/dp/1430219025
Optimisation is about making queries run faster, through code changes or indexes.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability