查询错误，列模糊

Question

该查询产生一条错误消息。为什么会这样？可以做些什么来纠正查询？

SELECT NAME, DATE 
FROM LETTER, LANGUAGE, CITY 
WHERE LANGUAGE = LANG_ID 
AND PLACE_SENT = CITY_ID ; 

错误：

Query could not be executed : 1052: Column 'LANGUAGE' in where clause is ambiguous

Answer 1

1：这意味着这两个表。你需要指定你想获得哪一个中提出LANGUAGE列。

第二：你需要使用table名称与column name避免列名ambiguouserror

SELECT LETTER.NAME, LETTER.DATE 
FROM LETTER , LANGUAGE, CITY 
WHERE LETTER.LANGUAGE = LANGUAGE.LANG_ID 
AND LETTER.PLACE_SENT = CITY.CITY_ID ; 

Answer 2

所以LANGUAUGE列存在于一个以上的表。因此，你需要澄清你想选择此列的表。请还可以添加的表名where条款

SELECT LETTER.NAME, LETTER.DATE 
FROM LETTER , LANGUAGE, CITY 
WHERE LETTER.LANGUAGE = LANGUAGE.LANG_ID 
AND LETTER.PLACE_SENT = CITY.CITY_ID ; 

Answer 3

在当我有猜测：

SELECT NAME, DATE 
FROM LETTER, LANGUAGE, CITY 
WHERE LETTER.LANGUAGE = LANG_ID 
AND PLACE_SENT = CITY_ID ; 

或

SELECT NAME, DATE 
FROM LETTER, LANGUAGE, CITY 
WHERE CITY.LANGUAGE = LANG_ID 
AND PLACE_SENT = CITY_ID ; 

或

SELECT NAME, DATE 
FROM LETTER, LANGUAGE, CITY 
WHERE LANGUAGE.LANGUAGE = LANG_ID 
AND PLACE_SENT = CITY_ID ; 

或

SELECT NAME, DATE 
FROM LETTER, LANGUAGE, CITY 
WHERE LANGUAGE.ID = LANG_ID 
AND PLACE_SENT = CITY_ID ; 

可能会解决您的问题。

Answer 4

有一个表名为LANGUAGE，属性名称为LANGUAGE。 我在你的查询中用粗体文本标记了它们。也确实提到了在where子句为table.attribute的 看看下面

SELECT名称，日期 从letter，语言，市 WHERE 表。语言 = LANG_ID AND 表。 PLACE_SENT = CITY_ID;