SELECT A.ID, A.NAME, A.DESC, B.COUNTB, C.COUNTC FROM A, B, C WHERE A.ID = B.AID AND A.ID = C.AID
SELECT A.ID, A.NAME, A.DESC FROM A LEFT OUTER JOIN (SELECT AID, COUNT(*) BCOUNT FROM B GROUP BY B.AID) BB ON A.ID = BB.AID LEFT OUTER JOIN (SELECT AID, COUNT(*) CCOUNT FROM C GROUP BY C.AID) CC ON A.ID = CC.AID
SELECT A.ID, A.NAME, A.DESC, BB.BCOUNT, CC.CCOUNT FROM A LEFT OUTER JOIN (SELECT AID, COUNT(*) BCOUNT FROM B GROUP BY B.AID) BB ON A.ID = BB.AID LEFT OUTER JOIN (SELECT AID, COUNT(*) CCOUNT FROM C GROUP BY C.AID) CC ON A.ID = CC.AID少了点东西
FROM A, B, C
WHERE A.ID = B.AID
AND A.ID = C.AID
SELECT A.ID, A.NAME, A.DESC
FROM A
LEFT OUTER JOIN (SELECT AID, COUNT(*) BCOUNT FROM B GROUP BY B.AID) BB
ON A.ID = BB.AID
LEFT OUTER JOIN (SELECT AID, COUNT(*) CCOUNT FROM C GROUP BY C.AID) CC
ON A.ID = CC.AID
SELECT A.ID, A.NAME, A.DESC, BB.BCOUNT, CC.CCOUNT
FROM A
LEFT OUTER JOIN (SELECT AID, COUNT(*) BCOUNT FROM B GROUP BY B.AID) BB
ON A.ID = BB.AID
LEFT OUTER JOIN (SELECT AID, COUNT(*) CCOUNT FROM C GROUP BY C.AID) CC
ON A.ID = CC.AID少了点东西