Regular expression problem

Question

Hi,

I'm searching a regex to filter out the following data

for example the text:

select *
from schema.[table name] d

i want to filter out the from component in 3 groups

1st group = from
2d group = schema.[table name]
3d group = d

the regex that i use (FROM)\s+([\[\]\w\.]+)\s+(AS\s+)?(\b\w+\b) does the trick but can't handle the spaces between the brackets so it only works when there are no spaces

select *
from schema.[tablename] d

How do change this regex expression so the ([\[\]\w\.]+) can also match the schema.[table name]

 

Thanks

Answer 1

Assuming that the schema is optional, and so are the brackets, you can use something like this:

@"(FROM)\s+((?:\w+\.)?(?:(?:\[[\w\s]+])|(?:\w+)))\s+(?:AS\s+)?(\w+)\b"

The pattern above uses non-capturing groups extensively so that the result groups aren't littered with extra captures. Adjust as you see fit.

Off topic: most special characters lose their special meaning in a character class (where it wouldn't make sense). This also apply to the dot, so you can just use "[ab.]" instead of "[ab\.]".

HTH
--mc