Executes the SELECT query but also returns the total of items.
It will remove the LIMIT clause if there is one to compute the total.
For the generated "total" query to work there are a couple of rules :
- The original query MUST start with SELECT and contains a FROM. All conditions between this SELECT keyword and
the FROM keyword will be removed and replaced by a COUNT(*).
- If the query contains a LIMIT clause, the last occurence will be remove and everything after it too.
If your query doesn't meet those rules, you'll have to retrieve the total another way...