Question

I have inherited a stored procedure which performs joins across eight tables, some of which contain hundreds of thousands of rows, then selects the top ten entries from the result of that join.

I have enough information at the start of the procedure to select those ten rows from a single table, and then perform those joins on those ten rows, rather than on hundreds of thousands of intermediate rows.

How do I select those top ten rows and then only do joins on those ten rows, instead of performing joins all of the thousands of rows in the table?

Answer 1

I should try:

SELECT * FROM
    (SELECT TOP 10 * FROM your_table
     ORDER BY your_condition) p
INNER JOIN second_table t
    ON p.field = t.field