我無法找到我的SQL代碼中的錯誤？

-1

所以我試圖列出每個客戶的數量和名稱，或者由銷售代表65或目前有文件訂單，或兩者，並且我不斷收到錯誤。我甚至在書中檢查瞭解決方案，我的代碼看起來是一樣的。這個錯誤告訴我什麼？我附上了本書給出的解決方案。 Solution 我無法找到我的SQL代碼中的錯誤？

mysql> SELECT CUSTOMER_NUM, CUSTOMER_NAME 
    -> FROM CUSTOMER 
    -> WHERE REP_NUM+'65' 
    -> UNION 
    -> SELECT C.CUSTOMER_NUM, CUSTOMER_NAME 
    -> FROM CUSTOMER C, ORDERS 0 
    -> WHERE C.CUSTOMER_NUM=0.CUSTOMER_NUM; 
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '0 
WHERE C.CUSTOMER_NUM=0.CUSTOMER_NUM' at line 6

來源

2016-11-02 Steberz

在未來，*請*告訴我們錯誤說* *什麼。 – ceejayoz

它是根據代碼 – Steberz

你有zero作爲別名是錯誤的原因。數字不允許別名。我想，而不是你ozero

SELECT CUSTOMER_NUM, CUSTOMER_NAME 
    FROM CUSTOMER 
    WHERE REP_NUM = '65' -- also here `=` should be used instead of `+` 
    UNION 
    SELECT C.CUSTOMER_NUM, CUSTOMER_NAME 
    FROM CUSTOMER C, ORDERS o 
    WHERE C.CUSTOMER_NUM=o.CUSTOMER_NUM;

來源

2016-11-02 01:57:44

謝謝！我很困惑，因爲提供的解決方案看起來像0而不是o – Steberz

用途EXISTS：

select c.* 
from customer c 
where rep_num = 65 or 
     exists (select 1 from orders o where c.customer_num = o.customer_num);

你的具體問題是，你已經使用了數作爲表的別名。你應該真的使用一封信。

然而，其他的事情浮現在腦海中：

union是一個資源豬，因爲它會帶來的開銷去除重複。這不是這個查詢所必需的。
數字（如65）不應包含在單引號中 - 這些應該用於字符串和日期。
你有一個+其中=被調用。

來源

2016-11-02 01:58:43

檢查你的語法，這是'65' =不+ '65'

mysql> SELECT CUSTOMER_NUM, CUSTOMER_NAME 
-> FROM CUSTOMER 
-> **WHERE REP_NUM+'65**' 
-> UNION 
-> SELECT C.CUSTOMER_NUM, CUSTOMER_NAME 
-> FROM CUSTOMER C, ORDERS 0 
-> WHERE C.CUSTOMER_NUM=0.CUSTOMER_NUM;

來源

2016-11-02 02:11:45 Tiutiu

我無法找到我的SQL代碼中的錯誤？

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