Dynamic MySQL Where Clause in Stored Procedure

You can use CASE statement to check for the value of @keywords, eg.

SELECT  col1, col2 
FROM    tblThreads 
WHERE   description LIKE  CASE WHEN @keywords IS NULL 
                            THEN description
                            ELSE CONCAT('%', @keywords, '%')
                            END
        AND
        price LIKE  CASE WHEN @price IS NULL 
                            THEN price
                            ELSE CONCAT('%', @price, '%')
                            END