How can I match a field in the MySql-Database with a regular expression that should be null or a defined string? In Javascript the expression would look like this (and in JS it works) /(.{0}|^ADO$)/
2 Answers
It might be clearest to use IFNULL so you can explictly indicate how you want to handle NULLs (I'm always looking for ways to make code easier to understand, rather than more tricksy). Perhaps something like this:
SELECT * from table where IFNULL(field, '') REGEXP 'whatever';
Comments
Use IS NULL, like this:
SELECT * FROM table WHERE (field IS NULL OR field = 'ADO')
1 Comment
andred
As a plain query this would be the right way to do it, you're right, but the problem I have is doing this within a regular expression.
null. The regex cannot tell the difference between a null var and a var containing the stringnull. Note also that/(.{0}|^ADO$)/will match any string as.{0}is the same as the empty expression which always matches. Your expression is equal to/(|^ADO$)/which is almost the same as/(^ADO$)?/.