T-SQL ESCAPE for Querying Underscores

In T-SQL the underscore is a special character when querying/filtering records. 





The following code will return all records and not only those with an underscore because the underscore acts like a wildcard if not escaped.




Select * from TableName

Where ColumnName Like '%_%'




Using ESCAPE in the query will make the special character such as the underscore a literate character.  The following code will return only those records that contain an underscore.




Select * from TableName

Where ColumnName Like '%\_% ESCAPE '\'




More information about ESCAPE