.net - Regular expression to find all table names in a query

Question

I am not that hot at regular expressions and it has made my little mind melt some what.

I am trying to find all the tables names in a query. So say I have the query:

SELECT one, two, three FROM table1, table2 WHERE X=Y

I would like to pull out "table1, table2" or "table1" and "table2"

But what if there is no where statement. It could be the end of the file, or there could be a group by or an order by etc. I know "most" of the time this will not be an issue but I don't like the idea of coding for "most" situations and knowing I have left a hole that could cause things to go wrong later.

Is this a doable Regex expression? Am I being a Regex pleb?

(P.S. this will be done in C# but presume that doesn't matter much).

Answer 1

RegEx isn't very good at this, as it's a lot more complicated than it appears:

• What if they use LEFT/RIGHT INNER/OUTER/CROSS/MERGE/NATURAL joins instead of the a,b syntax? The a,b syntax should be avoided anyway.
• What about nested queries?
• What if there is no table (selecting a constant)
• What about line breaks and other whitespace formatting?
• Alias names?

I could go on.

What you can do is look for an sql parser, and run your query through that.