The COL_NAME function returns a column’s name when you give it a table’s object ID and the column’s ID. This post uses it to turn the column IDs in index views into names, shows why a column ID is not a position once a column has been dropped, and explains the trap that returns a wrong name when the table lives in another database.
How to Check if a Column Exists in a SQL Server Table
To check if a column exists in a SQL Server table, call COL_LENGTH and test the result for NULL, or look the column up in sys.columns. This post compares the three common checks, including the schema trap in INFORMATION_SCHEMA and the three-part name for another database. It ends with a script that adds a column only when it is missing, and the batch rule that makes that script fail if you ignore it.
SQL SERVER – View Column Dependencies and Output Columns
To Identify Columns used in a view, I distinguish references from returned output columns. Those lists answer different questions.
EXECUTE AS LOGIN vs EXECUTE AS USER: Where Impersonation Stops
Your test passed as a user, yet the sales team still gets an error. Here is where each kind of impersonation stops, and how to get back out.
SQL SERVER – Msg 1833 – File Cannot be Reused Until After the Next BACKUP LOG Operation
Adding a file during a demo failed with Msg 1833: file cannot be reused until after the next BACKUP LOG operation. Here is the root cause.
SQL SERVER – FIX: Msg 35250 – The Connection to the Primary Replica is Not Active. The Command Cannot be Processed
A reader still got Msg 35250 after my first post, with no mirroring login error in the ERRORLOG. Here are the endpoint and service account checks I asked for.
Finding User Objects in master Created by Accident
Find user objects in master, inspect their purpose and dependencies, and prepare a safe move without removing deliberate server helpers.