Optional AND in WHERE statement MySQL

I'm trying to figure out how to allow optional AND statements where there is a LEFT OUTER JOIN since the table is optional when viewing records. However, I have a problem where there is开发者_如何学运维 no files, and in the WHERE statement, like this:

SELECT rec.record_id,
       rec.record_name,
       f.file_name,
       f.file_id
FROM
(
    records rec

    LEFT OUTER JOIN files f ON f.record_id = rec.record_id
)
WHERE rec.record_id = 4928 
AND f.file_approved = 1      <-- this is what returns a zero results

When I remove AND f.file_approved = 1 it returns a record, but when I leave it, it returns no record.

If a record contains no file records, it will not return anything. I need it to check it and if there are no files, it should still be able to return the record (without the files).

try moving the condition into the join statement, that way it will only join on the lines if they meet the condition

SELECT rec.record_id,
       rec.record_name,
       f.file_name,
       f.file_id
FROM
(
    records rec

    LEFT OUTER JOIN files f ON f.record_id = rec.record_id AND f.file_approved = 1
)
WHERE rec.record_id = 4928;

If yu dont want to force the condition, use the OR instead

WHERE 
  rec.record_id = 4928  
OR 
  f.file_approved = 1