SELECT using three tables w/ 1000+ entries - mysql

Question

For transaction listing I need to provide the following columns:
log_out.timestamp
items.description
log_out.qty
category.name
storage.name
log_out.dnr ( Representing the users id )
Table structure from log_out looks like this:
| id | timestamp | storageid | itemid | qty | categoryid | dnr |
| | | | | | | |
| 1 | ........ | 2 | 23 | 3 | 999 | 123 |
As one could guess, I only store the corresponding ID's from other tables in this table. Note: log_out.id is the primary key in this table.
To get the the corresponding strings, int's or whatever back, I tried two queries.
Approach 1
SELECT i.description, c.name, s.name as sname, l.*
FROM items i, categories c, storages s, log_out l
WHERE l.itemid = i.id AND l.storageid = s.id AND l.categoryid = c.id
ORDER BY l.id DESC
Approach 2
SELECT log_out.id, items.description, storages.name, categories.name AS cat, timestamp, dnr, qty
FROM log_out
INNER JOIN items ON log_out.itemid = items.id
INNER JOIN storages ON log_out.storageid = storages.id
INNER JOIN categories ON log_out.categoryid = categories.id
ORDER BY log_out.id DESC
They both work fine on my developing machine, which has approx 99 dummy transactions stored in log_out. The DB on the main server got something like 1100+ tx stored in the table. And that's where trouble begins. No matter which of these two approaches I run on the main machine, it always returns 0 rows w/o any error *sigh*.
First I thought, it's because the main machine uses MariaDB instead of MySQL. But after I imported the remote's log_out table to my dev-machine, it does the same as the main machine -> return 0 rows w/o error.
You guys got any idea what's going on ?

Answer 1

If the table has the data then it probably has something to do with JOIN and related records in corresponding tables. I would start with log_out table and incrementally add the other tables in the JOIN, e.g.:
SELECT *
FROM log_out;
SELECT *
FROM log_out
INNER JOIN items ON log_out.itemid = items.id;
SELECT *
FROM log_out
INNER JOIN items ON log_out.itemid = items.id
INNER JOIN storages ON log_out.storageid = storages.id;
SELECT *
FROM log_out
INNER JOIN items ON log_out.itemid = items.id
INNER JOIN storages ON log_out.storageid = storages.id
INNER JOIN categories ON log_out.categoryid = categories.id;
I would execute all the queries one by one and see which one results in 0 records. Additional join in that query would be the one with data discrepancy.

Answer 2

You're queries look fine to me, which makes me think that it is probably something unexpected with the data. Most likely the ids in your joins are not maintained right (do all of them have a foreign key constraint?). I would dig around the data, like SELECT COUNT(*) FROM items WHERE id IN (SELECT itemid FROM log_out), etc, and seeing if the returns make sense. Sorry I can't offer more advise, but I would be interested in hearing if the problem is in the data itself.