sql – 从另一个表的行批量更新表

2桌：

Employees
- EmployeeID
- LeadCount


Leads
- leadID
- employeeID

我想通过计算Leads表中具有相同EmployeeID的潜在客户数来更新Employees.LeadCount列.

注意：可能有多个具有相同employeeID的潜在客户,因此我必须执行disTINCT(SUM(employeeID)).

解决方法

UPDATE
    Employees E
SET
    E.LeadCount = (
        SELECT COUNT(L.EmployeeID)
        FROM Leads L
        WHERE L.EmployeeID = E.EmployeeID
    )