UNION vs UNION ALL comes down to duplicates: UNION removes them and UNION ALL keeps every row. This post tests both on two small store tables. It also covers sorting, a total row at the bottom, mixed operators and data type rules.
SQL SERVER – Return Specific Row to at the Bottom of the Resultset – T-SQL Script
How do I return a few chosen rows at the bottom of the entire resultset, in my own order? A T-SQL script on AdventureWorks shows how to do it.
UPDLOCK and READPAST for Queue Tables
UPDLOCK and READPAST let SQL Server queue workers claim different rows safely when transactions, retries, and completion rules are designed.
CASE Expression Pitfalls: NULL Tests and Data Type Precedence
Reproduce CASE expression traps with NULL tests, mixed result types, missing ELSE, and nesting, then apply clear rewrites.
SQL Server on a Virtual Machine: What Actually Changes
SQL Server on a virtual machine cannot see the host it is sharing. Why more virtual processors can be slower, what memory reservation buys you, why snapshots are not backups, and the four things I check first.
Loading a CSV Whose Columns Do Not Match the Table
Your supplier’s CSV has an extra column and a different order. Here is how to load it safely, with a header check and a staging table.
SQL SERVER – Get High Availability with SQL Server 2012
SQL Server 2012 offers several High Availability options, including up to four active secondaries. Here is what they give you and how a course can help.