PostgreSQL-别名列和
获取:错误:列»pjz«不存在PostgreSQL-别名列和,postgresql,having,column-alias,Postgresql,Having,Column Alias,获取:错误:列»pjz«不存在 我该怎么做呢?不能在having中使用别名,而必须在having clause中复制该语句。由于您只想检查null,因此可以执行以下操作: SELECT CASE WHEN SUM(X.Count)*3600 is null THEN '0' ELSE SUM(X.Count)*3600 END AS PJZ, X.Mass FROM X WHERE X.Ma
我该怎么做呢?不能在having中使用别名,而必须在having clause中复制该语句。由于您只想检查null,因此可以执行以下操作:
SELECT
CASE WHEN SUM(X.Count)*3600 is null THEN '0'
ELSE
SUM(X.Count)*3600
END AS PJZ,
X.Mass
FROM X
WHERE X.Mass > 2000
HAVING ((X.Mass / PJZ * 100) - 100) >= 10;
将其包装到派生表中:
SELECT coalesce(SUM(X.Count)*3600, 0) AS PJZ, X.Mass
FROM X
WHERE X.Mass > 2000
HAVING ((X.Mass / coalesce(SUM(X.Count)*3600, 0) * 100) - 100) >= 10;
(请注意,我添加了缺少的group by,否则查询将无效)其他选项是使用
语句将query by包围起来-例如:
SELECT CASE
WHEN PJZ = 0 THEN 100
ELSE PJZ
END as PJZ,
mass
FROM (
SELECT CASE
WHEN SUM(X.Count)*3600 is null THEN '0'
ELSE SUM(X.Count)*3600
END AS PJZ,
X.Mass
FROM X
WHERE X.Mass > 2000
GROUP BY X.mass
) t
WHERE PJZ = 0
OR ((X.Mass / PJZ * 100) - 100) >= 10;
在我看来,它比代码复制好得多,但现在我遇到了被零除的问题。PJZ可以是零。然后排除PJZ为零的行。或者根据您的要求,在CASE语句中返回1(或任何其他非零值),我不能排除这些行,因为我也想看到它们。如果PJZ为0,则:((X.Mass/PJZ*100)-100)应该为我显示100。所以我还需要另一个。。。
WITH x as (
SELECT coalesce(SUM(X.Count)*3600, 0) AS PJZ, X.Mass
FROM X
WHERE X.Mass > 2000
)
SELECT * from X WHERE PJZ >=10