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
)
