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

Answer 1

Constructing a regular expression is going to be the least of your problems. Depending on the flavor of SQL you expect to support with this code, the number of ways you can reference a table in a SQL statement is staggering.

PLUS, if the query includes a reference to a view or UDF, the information about what underlying tables won't even be in the string at all making it completely impractical to get that information by parsing it. Also, you'd need to be smart about detecting temporary tables and excluding them from your results.

If you must do this, a better approach would be to make use of the APIs to the particular database engine that the SQL was intended for. For example you could create a view based on the query and then use the DB Server api to detect dependencies for that view. The DB engine is going to be able to parse it much more reliably than you ever will without an enormous effort to reverse engineer the query engine.

If, by chance, you are working with SQL Server, here is an article about detecting dependencies on that platform: Finding Dependencies in SQL Server 2005