SELECT t.*,count(*),
level tpre_position, NVL(w.ID, 0) AS numr
FROM BASE_QUESTIONS t
LEFT JOIN BASE_TOPIC w
ON w.QUE_ID = t.POST_ID
CONNECT BY t.POST_ID = PRIOR t.POST_ID
AND LEVEL <= '5'
AND PRIOR DBMS_RANDOM.VALUE IS NOT NULL
请问我这个怎么在去关联另一张表,并统计其中的a = 1 and b = 2 的个数