SQL用于选择一列中具有重复值的所有行

I have a users table that has duplicate values in the employee_id column. I need to list all rows with duplicate employee_ids, along with their names. I need to see all users with a duplicate employee_id so I can de-conflict which values are valid.

我有一个users表，在employee_id列中有重复的值。我需要列出所有具有重复employee_ids的行及其名称。我需要查看所有具有重复employee_id的用户，以便我可以解除哪些值有效。

SELECT name,employee_id  
FROM users;

name     | employee_id
-----------------------
jason      12345
tom        34567 
jane       12345
will       01020
bill       12345

I need to return:

我需要回复：

name       | employee_id
-------------------------
jason        12345
jane         12345
bill         12345

I see similar questions, but I still can't get the correct syntax I need. With the below I am only getting one occurrence. I need all occurances with duplicate employee_id like above.

我看到类似的问题，但我仍然无法获得我需要的正确语法。以下我只会发生一次。我需要像上面那样重复employee_id的所有发生。

SELECT employee_id, MAX(name) 
FROM users 
GROUP BY employee_id 
HAVING COUNT(employee_id) > 1;

1 个解决方案

#1

You could use windowed COUNT:

您可以使用窗口COUNT：

SELECT sub.name, sub.employee_id
FROM (SELECT *, COUNT(*) OVER(PARTITION BY employee_id) AS c
      FROM users) AS sub
WHERE c > 1;

LiveDemo

LiveDemo

or simple IN:

或简单的IN：

SELECT *
FROM users
WHERE employee_id IN (SELECT employee_id 
                      FROM users 
                      GROUP BY employee_id 
                      HAVING COUNT(employee_id) > 1);

LiveDemo2

LiveDemo2

or correlated subquery:

或相关子查询：

SELECT name, employee_id
FROM users u
,LATERAL (SELECT COUNT(*) FROM users u2 WHERE u.employee_id = u2.employee_id) AS s(c)
WHERE c > 1;

SqlFiddleDemo

SqlFiddleDemo

#1