SQL加入，不確定複雜查詢中的確切語法

我希望查詢本身解釋了我想要做的事情。我遇到的麻煩該生產線是LEFT JOIN從業人員P於insolvencies.practitioner = practitioners.id，

SELECT DISTINCT  i.id   AS id, 
        i.company  AS company, 
        i.insolvencyDate AS insolvency_date, 
        i.city   AS city, 
        i.createdOn  AS createdOn, 
        1    AS rank_id, 
        t.entryCopy  AS insolvency_type, 
        i.businessNature AS business_nature, 
        p.name   AS pract_comp_name, 
        'I'    AS i_type 
    FROM  insolvencies i, 
     LEFT JOIN practitioners p ON insolvencies.practitioner = practitioners.id, 
     lookupcopy t 
    WHERE i.checked = 1  
     AND t.id  = i.insolvencyType 
     AND i.insolvencyDate >= {ts '2010-01-22 00:00:00'} 
     AND i.insolvencyDate <= {ts '2011-10-20 00:00:00'} 
     AND (LOWER(p.name) LIKE '%Hodgsons%') 
    GROUP BY  id

來源

2011-10-06 i-CONICA

爲什麼要混合ANSI-86和ANSI-92風格的加入的完美例子可能不是一個好主意 –

對我來說，在我的技能水平上，康拉德真的很有幫助。謝謝。 –

我認爲你正在尋找的東西是這樣的：

SELECT DISTINCT i.id AS id 
    , i.company AS company 
    , i.insolvencyDate AS insolvency_date 
    , i.city AS city 
    , i.createdOn AS createdOn 
    , 1 AS rank_id 
    , t.entryCopy AS insolvency_type 
    , i.businessNature AS business_nature 
    , p.name AS pract_comp_name 
    , 'I'  AS i_type 
    FROM insolvencies i 
    LEFT JOIN practitioners p ON insolvencies.practitioner = practitioners.id 
    CROSS JOIN lookupcopy t 
    WHERE i.checked = 1  
    AND t.id  = i.insolvencyType 
    AND i.insolvencyDate >= {ts '2010-01-22 00:00:00'} 
    AND i.insolvencyDate <= {ts '2011-10-20 00:00:00'} 
    AND (LOWER(p.name) LIKE '%Hodgsons%') 
GROUP BY id

表之間的,相同CROSS JOIN。

但無論如何，你應該閱讀約cross join,inner join和outer join並使用最適合您的情況。

來源

2011-10-06 16:50:55 DavidEG

從[MySQL參考]（http://dev.mysql.com/doc/refman/5.0/en/join.html）'在MySQL中，CROSS JOIN是一個等效於INNER JOIN的語法（他們可以互相替換）'那麼你在SQL之後寫了什麼樣的有趣的 –

是的，但是根據標準瞭解其差異並使用它是很好的。並非所有的RDBMS都是MYSQL :) – DavidEG

您需要insolvencies i,後刪除逗號，使LEFT JOIN適用於表，否則LEFT JOIN是被視爲一個獨立的表，交叉應用，這是無效的：

FROM insolvencies i 
      --  ^remove comma 
    LEFT JOIN...

來源

2011-10-06 16:45:28 mellamokb

的問題是，你的WHERE子句引用LEFT JOIN起來表

WHERE i.checked = 1  
     AND t.id  = i.insolvencyType 
     AND i.insolvencyDate >= {ts '2010-01-22 00:00:00'} 
     AND i.insolvencyDate <= {ts '2011-10-20 00:00:00'} 
     AND (LOWER(p.name) LIKE '%Hodgsons%')

如果LEFT JOIN找不到匹配項，則p.Name將爲NULL。通過在WHERE子句中檢查p.Name，可以使LEFT JOIN充當一個FULL JOIN。如果需要檢查名稱，它應該是LEFT JOIN中ON表達式的一部分

來源

2011-10-06 16:46:06 Sparky

這裏有很多問題。首先，我拿出逗號並正確加入了lookupcopy。我不是100％確定你的最終目標，但有以下幾點入手：

SELECT DISTINCT i.id AS id, 
       i.company AS company, 
       i.insolvencyDate AS insolvency_date, 
       i.city AS city, 
       i.createdOn AS createdOn, 
       1 AS rank_id, 
       t.entryCopy AS insolvency_type, 
       i.businessNature AS business_nature, 
       p.name AS pract_comp_name, 
       'I' AS i_type 
    FROM insolvencies i 
     INNER JOIN lookupcopy t on (t.id = i.insolvencyType) 
     LEFT JOIN practitioners p ON i.practitioner = p.id 
    WHERE i.checked = 1 
     AND i.insolvencyDate >= {ts '2010-01-22 00:00:00'} 
     AND i.insolvencyDate <= {ts '2011-10-20 00:00:00'} 
     AND (LOWER(p.name) LIKE '%Hodgsons%') 
    GROUP BY id

如果仍然有問題，請發表您的實際誤差。

另外，還有一件事：在where子句中引用p.Name將導致從業者和破產人之間的內部聯接。這是打算嗎？

來源

2011-10-06 16:49:42 NotMe

+1內部連接 – eykanal

SQL加入，不確定複雜查詢中的確切語法

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