SQL 1
MySQL的計數問題
SELECT (
COUNT(contract.contract_notesid) + (SELECT COUNT(contract_notesid)
FROM quotation WHERE quotation.contract_notesid = contract.contract_notesid)
) AS total
FROM contract where contract_notesid = '48'
total 2
SQL 2
SELECT (
COUNT(contract.contract_notesid) + (SELECT COUNT(contract_notesid)
FROM quotation WHERE quotation.contract_notesid = 48)
) AS total
FROM contract where contract_notesid = '48'
total 6
contract table
:2條記錄quotation table
:4條記錄
1.爲什麼不同數?
2. SQL 2
,有沒有什麼更好的辦法呢?(total: 6
)
取決於你想要做什麼。你試圖完成什麼? – rwilliams 2010-11-08 08:02:08
@ r-dub從2個表中獲得總數 – love 2010-11-08 08:04:56
嘗試從表中手動計數contract_notesid = 48的合同...將您的手動結果與上面的兩個sql查詢進行比較......哪一個符合是正確的查詢。 – yonan2236 2010-11-08 08:06:53