Question

我需要按日期对日志表中的记录进行分组，并在该特定日期对由regrular员工或specialEmployee进行访问的次数进行分组。访问应该是不同的，例如，如果用户类型登录两次，那么它应该只计算当天一次

Type
PK typeId
name

Employee
PK empId
firstName
lastName
FK typeId     


Log
PK logId
FK empId
date

我已尝试过以下查询，但无济于事。当我用计数替换sum / case时它可以工作但是我无法明确指定哪种类型的用户

SELECT L.`date`
SUM(DISTINCT CASE WHEN E.typeId =1 THEN 1 ELSE 0 END) as specialEmployeeAccesses,
SUM(DISTINCT CASE WHEN E.typeId=2 THEN 1 ELSE 0 END) as regularEmployeeAccesses
FROM LOG L
INNER JOIN
Employee E
ON E.empId = L.empId
GROUP BY L.`date`

Answer 1

尝试：

SELECT L.`date`,
       COUNT(DISTINCT CASE WHEN E.typeId=1 THEN E.empId END) 
            as specialEmployeeAccesses,
       COUNT(DISTINCT CASE WHEN E.typeId=2 THEN E.empId END) 
            as regularEmployeeAccesses
FROM LOG L
INNER JOIN Employee E
ON E.empId = L.empId
GROUP BY L.`date`

Mysql计算表中的不同用户

1 个答案: