MySQL查詢：如何修復錯誤1052（不明確的列）

Question

我在運行CUST_NUM不明確的以下兩個查詢時，不斷收到錯誤消息。我怎樣才能解決這個問題？

SELECT INV_NUM, CUST_NUM, CUST_LNAME, CUST_FNAME, INV_DATE, INV_AMOUNT 
FROM CH08_INVOICE i 
INNER JOIN CH08_CUSTOMER c1 ON (i.CUST_NUM = c1.CUST_NUM) 
WHERE CUST_BALANCE>=1000; 


SELECT CUST_LNAME, CUST_FNAME 
FROM CH08_CUSTOMER c1 JOIN CH08_CUSTOMER_2 c2 
ON (c1.CUST_LNAME = c2.CUST_LNAME AND c1.CUST_FNAME = c2.CUST_FNAME); 

Answer 1

SELECT i.INV_NUM, i.CUST_NUM, i.CUST_LNAME, i.CUST_FNAME, i.INV_DATE, i.INV_AMOUNT FROM CH08_INVOICE i INNER JOIN CH08_CUSTOMER c1 ON (i.CUST_NUM = c1.CUST_NUM) WHERE i.CUST_BALANCE>=1000; 

SELECT c1.CUST_LNAME, c1CUST_FNAME FROM CH08_CUSTOMER c1 JOIN CH08_CUSTOMER_2 c2 ON (c1.CUST_LNAME = c2.CUST_LNAME AND c1.CUST_FNAME = c2.CUST_FNAME); 

請檢查該查詢

Answer 2

不明確的列意味着數據庫不知道它必須使用該表中的列。

使用

SELECT INV_NUM, i.CUST_NUM ... 

或

SELECT INV_NUM, c1.CUST_NUM ... 

爲顯式定義表嘗試。