Custom query on custom table fails

Question

I have a custom table in my Wordpress database and have a custom query that runs against it and displays the data in a custom template.

This is the query

 $query ="
                        SELECT *
                        FROM cp
                        WHERE year = $cp_year
                        AND quarter = $cp_quarter
                        AND volume = $cp_volume
                        AND page <= $cp_page
                        ORDER BY page DESC
                        LIMIT 1
                        ";

This works fine as long as $cp_volume is an integer but if it is a string variable such as 1a the query fails with this error message

WordPress database error: [Unknown column '2a' in 'where clause'] SELECT * FROM cp WHERE year = 1911 AND quarter = 4 AND volume = 2a AND page <= 1475 ORDER BY page DESC LIMIT 1

volume is declared as varchar in the database table.

I have been struggling and searching on Google for several hours without success. Anyone got any bright ideas please?

Answer 1

On volume pass single quote in parameter. Now your query is

SELECT * FROM cp WHERE year = '1911' AND quarter = '4' AND volume = '2a' AND page <= '1475' ORDER BY page DESC LIMIT 1   Try this code