查询抛出错误； "column ambiguously defined"

Question

我是运行查询为

SELECT LOCATION_OID,UPPER(NAME) AS LOCATION_NAME FROM LOCATION LEFT OUTER JOIN LOCATION_CHILD_LOCATION parent on (parent.LOCATION_OID = LOCATION.LOCATION_OID)

有两个table LOCATION和LOCATION_CHILD_LOCATION，Location有456条记录，location_child_location有4条记录。 location_child_location 中的记录映射到来自父级的 location_oid，即位置 table。为什么此查询会出错？

Answer 1

您必须在 select 子句中的 LOCATION_OID 前面添加 table 名称：

SELECT LOCATION.LOCATION_OID,UPPER(NAME) AS LOCATION_NAME FROM LOCATION LEFT OUTER JOIN LOCATION_CHILD_LOCATION on (parent.LOCATION_OID = LOCATION.LOCATION_OID)

Answer 2

您需要指定要从中获取 LOCATION_OID 的 table，否则分析器会混淆它必须查找哪个 table 来获取数据。试试这个：

SELECT LOCATION.LOCATION_OID,UPPER(NAME) AS LOCATION_NAME 
FROM LOCATION LEFT OUTER JOIN LOCATION_CHILD_LOCATION parent
 on (parent.LOCATION_OID = LOCATION.LOCATION_OID)

Answer 3

尝试以下查询，其中正确提及命名以避免 Table 命名冲突：

SELECT l.LOCATION_OID,UPPER(NAME) AS LOCATION_NAME 
FROM LOCATION as l
LEFT OUTER JOIN LOCATION_CHILD_LOCATION parent on (parent.LOCATION_OID = LOCATION.LOCATION_OID)

Answer 4

为每个表使用别名而不是混合使用这两种方法（使用和不使用别名）：

SELECT L.LOCATION_OID
    ,UPPER(L.NAME) AS LOCATION_NAME
FROM LOCATION L
LEFT OUTER JOIN LOCATION_CHILD_LOCATION P ON P.LOCATION_OID = L.LOCATION_OID

希望这会有所帮助。

查询抛出错误； "column ambiguously defined"

Query throwing error; "column ambiguously defined"

mysql

sql

oracle

oracle11g