Question

How does one join say, on tableD.id = tableC.id AND tableD.id = tableE.id? both tableD and E may have 0 rows and I need to count them ie. SELECT COUNT(E.id). The problem is I don’t know where to declare the table identifiers.

I’ve tried:

FROM tableB B, tableD D, tableE E …

LEFT JOIN (tableC C, tableD D) ON …

SELECT B.*, COUNT(C.id) AS cCount 
FROM tableB B
LEFT JOIN (tableC C)
ON (B.id = C.id)
GROUP BY B.id

Answer 1

It is a little difficult to tell from your question what you’re looking for, but I believe this is it:

SELECT B.*, COUNT(C.id) AS cCount 
FROM tableB AS B
LEFT JOIN tableC AS C ON B.id = C.id
LEFT JOIN tableD AS D ON C.Id = D.Id
LEFT JOIN tableE AS E ON D.Id = E.Id
GROUP BY B.id