[sql] Why does using an Underscore character in a LIKE filter give me all the results?

I wrote the below SQL query with a LIKE condition:

SELECT * FROM Manager
WHERE managerid LIKE '_%'
AND managername LIKE '%_%'

In the LIKE I want to search for any underscores %_%, but I know that my columns' data has no underscore characters.

  • Why does the query give me all the records from the table?

Sample data:

create table Manager(
    id int
    ,managerid varchar(3)
    ,managername varchar(50)
    );

insert into Manager(id,managerid,managername)values(1,'A1','Mangesh');
insert into Manager(id,managerid,managername)values(2,'A2','Sagar');
insert into Manager(id,managerid,managername)values(3,'C3','Ahmad');
insert into Manager(id,managerid,managername)values(4,'A4','Mango');
insert into Manager(id,managerid,managername)values(5,'B5','Sandesh');

Sql-Fiddle

This question is related to sql sql-server

The answer is


As you want to specifically search for a wildcard character you need to escape that

This is done by adding the ESCAPE clause to your LIKE expression. The character that is specified with the ESCAPE clause will "invalidate" the following wildcard character.

You can use any character you like (just not a wildcard character). Most people use a \ because that is what many programming languages also use

So your query would result in:

select * 
from Manager
where managerid LIKE '\_%' escape '\'
and managername like '%\_%' escape '\';

But you can just as well use any other character:

select * 
from Manager
where managerid LIKE '#_%' escape '#'
and managername like '%#_%' escape '#';

Here is an SQLFiddle example: http://sqlfiddle.com/#!6/63e88/4


You can write the query as below:

SELECT * FROM Manager
WHERE managerid LIKE '\_%' escape '\'
AND managername LIKE '%\_%' escape '\';

it will solve your problem.


Underscore is a wildcard for something. for example 'A_%' will look for all match that Start whit 'A' and have minimum 1 extra character after that


In case people are searching how to do it in BigQuery:

  • An underscore "_" matches a single character or byte.

  • You can escape "\", "_", or "%" using two backslashes. For example, "\%". If you are using raw strings, only a single backslash is required. For example, r"\%".

WHERE mycolumn LIKE '%\\_%'

Source: https://cloud.google.com/bigquery/docs/reference/standard-sql/operators


The underscore is the wildcard in a LIKE query for one arbitrary character.

Hence LIKE %_% means "give me all records with at least one arbitrary character in this column".

You have to escape the wildcard character, in sql-server with [] around:

SELECT m.* 
FROM Manager m 
WHERE m.managerid    LIKE  '[_]%'
AND   m.managername  LIKE '%[_]%'

See: LIKE (Transact-SQL)

Demo