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[英]How to return all records having only integer values in a specific column?
[英]How to delete all duplicates in one column and return only those that has date in next column in SQL?
似乎是非常直接的 select 查询与聚合。 你试过什么,你遇到了什么错误或问题
SELECT Account, max(last_active) as Last_active
FROM TableName
WHERE last_active is not null
GROUP BY Account
也许你不想要最近的活跃......
所以也许:但这会显示重复的帐户,其中记录了所有“Last_active”日期......
SELECT Account, last_active
FROM TableName
WHERE last_active is not null
GROUP BY Account
您好,我刚刚在 MySQL 中制作了一个示例表,其中包含大约 200,000 条记录,其中一半是重复的。
以下查询效果很好。
SELECT * FROM TableName
WHERE last_active IS NOT NULL
AND 1 GROUP BY account
现在如果你想把它保存到一个新表中,你可以
CREATE TABLE newTableName as
SELECT * FROM TableName
WHERE last_active IS NOT NULL
AND 1 GROUP BY account
我会同意 xQbert 但是我会在 SELECT 之后添加一个 DISTINCT 以防万一帐户在同一日期激活两次(如果这是列的格式)并且两者都被记录
SELECT DISTINCT Account, max(last_active) as Last_active
FROM TableName
WHERE last_active is not null
GROUP BY Account
考虑下面的简单方法
select * from your_table
qualify count(*) over account = 1
and countif(last_active is null) over account = 0
window account as (partition by account)
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