SQL Server Escape an Underscore

Question

How do I escape the underscore character?

I am writing something like the following where clause and want to be able to find actual entries with _d at the end.

Where Username Like '%_d'

Answer 1

T-SQL Reference for LIKE for SQL Server 2000:

You can use the wildcard pattern matching characters as literal characters. To use a wildcard character as a literal character, enclose the wildcard character in brackets. The table shows several examples of using the LIKE keyword and the [ ] wildcard characters.

For your case:

... LIKE '%[_]d'

Answer 2

Obviously @Lasse solution is right, but there's another way to solve your problem: T-SQL operator LIKE defines the optional ESCAPE clause, that lets you declare a character which will escape the next character into the pattern.

For your case, the following WHERE clauses are equivalent:

WHERE username LIKE '%[_]d';            -- @Lasse solution
WHERE username LIKE '%$_d' ESCAPE '$';
WHERE username LIKE '%^_d' ESCAPE '^';

Answer 3

These solutions totally make sense. Unfortunately, neither worked for me as expected. Instead of trying to hassle with it, I went with a work around:

select * from information_schema.columns 
where replace(table_name,'_','!') not like '%!%'
order by table_name

Answer 4

This worked for me, just use the escape '%\_%'