MySQL: What is a reverse version of LIKE?

Question

LIKE operator in MySql is used to find rows that contain our query text, for example:

select name from user where name like \"%john%\"

Answer 1

Here's a way you can achieve what you describe:

SELECT name FROM user 
WHERE 'John Smith and Peter Johnson are best friends' LIKE
  CONCAT('%', name, '%')

Answer 2

This is a text indexing problem. If I get it right, your task is to find all references to people in a free-form text, and has nothing to do with LIKE or NOT LIKE.

In a general form, the database table against which you're looking for references acts as a dictionary to some text-indexing algorithm. Build an index on input string using this dictionary and hopefully you will get some matches.

Answer 3

select name
from users
where instr('John Smith and Peter Johnson', name) > 0

I would rather use this method instead of:

select *
from users
WHERE  'John Smith and Peter Johnson' LIKE CONCAT('%', name ,'%')

because if there is any chance that the name could contain the % or _ character (eg. name='v%alue') then the above query would still return that record incorrectly. Also note that if your column could contain backslashes and/or "C escape characters" then they would also need to be escaped. This is all explained in MySQL String Comparison Functions. For example the below SQL would return 1:

SELECT 'val\%ue' LIKE CONCAT('%', 'al\\\\\%u' ,'%');

The single backslash needed to be escaped with \\\\ and the % character was escaped: \%.