Question

I’m working on the following SELECT statement:

SELECT *
FROM table1
LEFT JOIN table2 ON table2.contentid = table3.id AND table2.tmplid = table1.id
WHERE table2.value = "test"

I’m getting the following error:

Execution of a query to the database failed – Unknown column
‘table3.id’ in ‘on clause’ »

What am I doing wrong?

Answer 1

This is your problem:

LEFT JOIN table2 ON table2.contentid = table3.id

You can’t have any table in your ON clause that’s not part of the join (in this case, table3).

Did you mean this instead:

SELECT *
FROM   table1
       LEFT JOIN table2
              ON table1.id = table2.tmplid
       LEFT JOIN table3
              ON table2.contentid = table3.id
WHERE  table2.value = "test"