MIcrosoft Documentation: UPDATE (Transact-SQL)

Useful for historical logging, the values present have the before and after values for the columns that are changed using the monikers of deleted and inserted


DECLARE  @Output TABLE ( ValueOld VARCHAR(100), ValueNew VARCHAR(100) )

UPDATE   TableName
SET      ColumnName = @NewValue
OUTPUT   deleted.ColumnName, inserted.ColumnName INTO @Output
WHERE    TableIndex = @TableIndex