SQL SELECT和UPDATE返回不同的結果

Question

我可能需要你對這個幫助... 我有以下MySQL查詢：

SELECT * FROM dbName1.Prospects A 
LEFT JOIN dbName2.inbox B ON 
      substring(A.ProspectCellPhone, 2) = substring(B.SenderNumber, 4) OR 
      substring(A.ProspectCellPhone, 3) = substring(B.SenderNumber, 4) OR 
      substring(A.ProspectCellPhone, 4) = substring(B.SenderNumber, 4) 
LEFT JOIN dbName1.User C ON A.Username = C.Username 
WHERE B.TextDecoded IS NOT NULL 
AND substring(B.SenderNumber,1,1) = '+' 
AND B.NotificationFlag = '0' 

它會返回125結果...... 但是，當我嘗試使用更新相同的查詢，它只返回45更新結果... 更新查詢：

UPDATE dbName1.Prospects A 
LEFT JOIN dbName2 B ON 
      substring(A.ProspectCellPhone, 2) = substring(B.SenderNumber, 4) OR 
      substring(A.ProspectCellPhone, 3) = substring(B.SenderNumber, 4) OR 
      substring(A.ProspectCellPhone, 4) = substring(B.SenderNumber, 4) 
LEFT JOIN dbName1.User C ON A.Username = C.Username 
SET B.NotificationFlag = '1' 
WHERE B.TextDecoded IS NOT NULL 
AND substring(B.SenderNumber,1,1) = '+' 
AND B.NotificationFlag = '0' 

難道我做錯什麼事上更新查詢？

非常感謝您的幫助...

Answer 1

嘗試使用相同的語句，你的情況二號線是在兩個不同的語句：

在Select語句是：

LEFT JOIN dbName2.inbox B ON 

在Update語句是：

LEFT JOIN dbName2 B ON 

Answer 2

運行此查詢檢查REA l表B中的記錄數加入。

Select distinct B.some_unique_field from dbName2.inbox B 
Left Join dbName1.Prospects A ON 
      substring(A.ProspectCellPhone, 2) = substring(B.SenderNumber, 4) OR 
      substring(A.ProspectCellPhone, 3) = substring(B.SenderNumber, 4) OR 
      substring(A.ProspectCellPhone, 4) = substring(B.SenderNumber, 4) 
WHERE B.TextDecoded IS NOT NULL 
AND substring(B.SenderNumber,1,1) = '+' 
AND B.NotificationFlag = '0'; 

希望我的查詢是正確的:)

Answer 3

你的選擇，因爲你b上做一個更新不匹配UDPATE所以basicaly它減少了對a JOIN b和選擇是a LEFT JOIN b LEFT JOIN C。 A中的多於一行可以匹配B中的一行，因此您可以獲得比B中的不同行更多的結果。試試這個：

SELECT DISTINCT b.ID FROM dbName1.Prospects A 
JOIN dbName2.inbox B ON 
substring(A.ProspectCellPhone, 2) = substring(B.SenderNumber, 4) OR 
substring(A.ProspectCellPhone, 3) = substring(B.SenderNumber, 4) OR 
substring(A.ProspectCellPhone, 4) = substring(B.SenderNumber, 4) 
WHERE B.TextDecoded IS NOT NULL 
AND substring(B.SenderNumber,1,1) = '+' 
AND B.NotificationFlag = '0'