Using Regular Expressions to Parse SQL

Reedick, Andrew jr9445 at ATT.COM
Tue Feb 5 16:28:23 CET 2008

> -----Original Message-----
> From: at [mailto:python-
> at] On Behalf Of ct60 at
> Sent: Tuesday, February 05, 2008 9:31 AM
> To: python-list at
> Subject: Using Regular Expressions to Parse SQL
> My pattern does not even come close.
> Any help would be greatly appreciated.  My goal is to analyse a large
> number of SQL querys to try to identify the join field and see where
> indexing might make sense.
> While I am mostly interested in understanding regular expressions, I
> would also be interested in knowing about any Python SQL parsers out
> there.

Python's regexes are a tad odd compared to Perl (or Perl's regexes are
odd.  Relativity.)  You need re.DOTALL to handle newlines in the sql:
	Make the "." special character match any character at all,
including a newline; without this flag, "." will match anything except a

import re

s= ''' FROM ((qry_Scores_Lookup1 INNER JOIN CSS_Rpt1 ON
(qry_Scores_Lookup1.desc = CSS_Rpt1.desc) AND
(qry_Scores_Lookup1.lastcdu = CSS_Rpt1.lastcdu))'''

pat =
m = re.compile(pat, re.DOTALL).match(s)
if m:
	print m

('(qry_Scores_Lookup1.desc = CSS_Rpt1.desc) ', '(qry_Scores_Lookup1.desc
= CSS_Rpt1.desc)')

You should be able to tweak the regex to get the exact matches you want.

An alternative to writing a lengthy regex might be to just grab
everything after the ON and then string split on "AND".


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