Question

I am having a hard time creating a mySQL join statement.

The issue is that it seems to return the correct results, but it returns duplicates.

$result= mysql_query("SELECT Photos.Filename, Photos.Filetype
FROM Photos, PhotoUserTags
WHERE PhotoUserTags.User_ID IN ($friendlist) && PhotoUserTags.Photo_ID = Photos.Photo_ID && Photos.Event_ID = $eid");

I am new to these statements, any help or guidance is greatly appreciated.

Answer 1

For one, the logical and in mysql is not && but AND, like this:

SELECT * from table WHERE field1 = 'value1' AND field2 = 'value2';

You should also use the newer join syntax like this:

SELECT Photos.Filename, Photos.Filetype
FROM Photos, PhotoUserTags
INNER JOIN PhotoUserTags ON PhotoUserTags.Photo_ID = Photos.Photo_ID
WHERE PhotoUserTags.User_ID IN ($friendlist)
  AND Photos.Event_ID = $eid
GROUP BY Photos.Photo_ID

Note the join expression (I used inner join, assuming a matching record needs to exist in both tables) – it makes your where cleaner and easier to read.