FROM中的子查询必须具有别名

Question

我有这个我在PostgreSQL中编写的查询返回错误说:

[错误]错误:第
3行:FROM(选择DISTINCT(可识别)AS made_only_recharge

这是整个查询:

SELECT COUNT (made_only_recharge) AS made_only_recharge
FROM (
    SELECT DISTINCT (identifiant) AS made_only_recharge
    FROM cdr_data
    WHERE CALLEDNUMBER = '0130'
    EXCEPT
    SELECT DISTINCT (identifiant) AS made_only_recharge
    FROM cdr_data
    WHERE CALLEDNUMBER != '0130'
)

我在Oracle中有一个类似的查询工作正常.唯一的变化是我EXCEPT在Oracle中的位置我用MINUS关键字取代了它.我是Postgres的新手,不知道它的要求.处理这个问题的正确方法是什么？

Answer 1

ALIAS在子查询上添加一个,

SELECT  COUNT(made_only_recharge) AS made_only_recharge
FROM    
    (
        SELECT DISTINCT (identifiant) AS made_only_recharge
        FROM cdr_data
        WHERE CALLEDNUMBER = '0130'
        EXCEPT
        SELECT DISTINCT (identifiant) AS made_only_recharge
        FROM cdr_data
        WHERE CALLEDNUMBER != '0130'
    ) AS derivedTable                           -- <<== HERE