The answer to my puzzle on Converting Money to DECIMAL(5,2): why it fails with arithmetic overflow, and why DECIMAL(7,2) works, since precision includes scale.
CONCAT: Missing Inputs Produce Present Text
CONCAT builds display text from available inputs. Preserve missing-source flags when output alone cannot prove completeness.
Unpivoting Columns Into Rows With CROSS APPLY and VALUES
Use CROSS APPLY and VALUES for unpivoting columns, retain nulls deliberately, preserve labels, and turn paired fields into aligned rows.
geometry STIsEmpty: Empty Shapes Are Different From SQL NULL
geometry STIsEmpty tests whether an existing spatial instance has an empty point set. I keep that condition separate from SQL NULL. A missing database value and a present empty geometry are different inputs.
How to Practise SQL Without a Real Database
You can practise SQL with small invented tables, generated rows, and repeatable exercises without access to a company's production database.
Replaying a Production Workload After Distributed Replay
Capture a production workload with Extended Events and replay it on a restored copy using WorkloadTools or ostress after Distributed Replay.
SQL SERVER – FIX ERROR 3702 Cannot drop database “MyDBName” because it is currently in use
Error 3702: cannot drop database because it is currently in use. Set it to SINGLE_USER WITH ROLLBACK IMMEDIATE, then drop it. Best kept for demo servers.