SQL和運營工作不正常

Question

我有以下兩個表

LandParcels表

Blockid ParcelNo storPri 
======= ======== ======= 
52000105 3  State 
52000105 4  Private 
52000105 5  State 

操作表

Blockid ParcelNo ActionTaken 
======= ======== =========== 
52000105 3  Received 
52000105 3  Send to Computer 
52000105 4  Received 
52000105 5  Received 

我想找到的記錄Received但不Send to Computer

這是我的查詢

select 
    l.blockid, l.parcelno 
from 
    landparcels l 
left join 
    actions ac on l.blockid = ac.blockid and l.parcelno = ac.parcelno 
where 
    ac.actiontaken = 'Received' 
    and ac.actiontaken <> 'Send to Computer' 
    and ac.blockid = 52000105 

結果是

Blockid ParcelNo 
======= ======== 
52000105 3 
52000105 4 
52000105 5 

我想ParcelNo 4和5

Answer 1

請注意，在任何常用數據庫產品中，您都很難在AND運算符中發現一個簡單的錯誤。這裏的問題不是數據庫引擎沒有產生正確的結果，而是你不明白AND運算符的作用。

看看你的情況ac.actiontaken = 'Received' AND ac.actiontaken <> 'Send to Computer'。將要發生的事情是，引擎將檢查輸出中的每個可能的行，並確定它是否符合您指定的條件。那麼，對於第一行，actiontaken是否是'Received'？是。 actiontaken不是'Send to Computer'嗎？當然。所以這個行有資格。

事實上，任何一行的actiontaken「接收」將有資格，因爲根據定義，它也確實actiontaken 該行是不「發送到計算機」。

有很多方法可以得到你想要的答案。這裏是我的首選之一：

SELECT DISTINCT a.blockid, a.parcelno FROM actions a 
WHERE a.blockid = 52000105 AND a.actiontaken = 'Received' AND NOT EXISTS 
    (SELECT * FROM actions a2 WHERE a2.blockid = a.blockid AND 
            a2.parcelNo = a.parcelNo AND 
            a2.actiontaken = 'Send to Computer') 

Answer 2

select a.blockid 
     ,a.parcelno 
    from landparcels a 
    join actions  b on(a.blockid = b.blockid and a.parcelno = b.parcelno) 
where b.action_taken in('Received', 'Send to Computer') 
    and a.blockid = 52000105 
group 
    by a.blockid 
     ,a.parcelno 
having count(*) = 1 
    and min(b.action_taken) = 'Received'; 

或東西少花哨，可以找兩個1出的特殊情況外延伸：

select a.blockid 
     ,a.parcelno 
    from landparcels a 
    join actions  b on(a.blockid = b.blockid and a.parcelno = b.parcelno) 
where b.blockid = 52000105 
    and b.action_taken = 'Received' 
    and not exists(
     select 'x' 
     from actions x 
     where x.action_taken = 'Send to Computer' 
     and b.blockid = x.blockid 
     and b.parcelno = x.parcelno 
    ); 

我剛剛意識到你不需要joi ñ與landparcels，根據您的要求，但我保持原樣，以防您的真實需求需要該表中的數據。

更新 添加塊標識過濾

Answer 3

如果你的數據庫支持tuple在where條款，儘量響應

select * 
from landparcels 
where (blockid, parcelno) in 
(
    select blockid, parcelno 
    from actions 
    where actiontaken = 'Received' 
) 
and (blockid, parcelno) not in 
(
    select blockid, parcelno 
    from actions 
    where actiontaken = 'Send to Computer' 
) 

編輯marc_s：否則，試試這個版本，我認爲這是ANSI，而不是

select * 
from landparcels as p 
where exists 
(
    select 1 
    from actions 
    where actiontaken = 'Received' 
    and blockid = p.blockid 
    and parcelno = p.parcelno 
) 
and not exists 
(
    select 1 
    from actions 
    where actiontaken = 'Send to Computer' 
    and blockid = p.blockid 
    and parcelno = p.parcelno 
) 

Answer 4

你沒有說你所使用的數據庫系統 - 但SQL Server上，你可以使用此查詢的位置：

SELECT 
    lp.* 
FROM 
    dbo.LandParcels lp 
WHERE 
    EXISTS(SELECT * FROM abo.ActionTaken a 
      WHERE a.blockid = lp.blockid 
      AND a.parcelno = lp.parcelno 
      AND a.ActionTaken = 'Received') 
    AND NOT EXISTS(SELECT * FROM dbo.ActionTaken a 
        WHERE a.blockid = lp.blockid 
        AND a.parcelno = lp.parcelno 
        AND a.ActionTaken = 'Send to Computer') 

這導致了這個輸出這裏：

blockid parcelno storePrio 
52000105  4   Private 
52000105  5   State 

Answer 5

SELECT Blockid, PacelNo FROM LandParcels 
WHERE (ParcelNo IN (SELECT ParcelNo FROM Actions WHERE ActionTaken = 'Received') 
AND (ParcelNo NOT IN (SELECT ParcelNo FROM Actions WHERE ActionTaken = 'Send to Computer'))) 

Answer 6

上@ Kirakun的「行建設者的回答進一步的變化，依然是ISO/ANSI語法，但是這是在SQL Server確實支持：

SELECT blockid, parcelno 
    FROM landparcels 
INTERSECT 
SELECT blockid, parcelno 
    FROM actions 
WHERE actiontaken = 'Received' 
EXCEPT 
SELECT blockid, parcelno 
    FROM actions 
WHERE actiontaken = 'Send to Computer';