找到丢失的记录

Question

三个表以下列方式相互连接：
Employee (ID, name) 到 Salary (ID, Employee_id, Vendor_id, total_amount, date_paid) 按员工 ID
工资（ID、Employee_id、Vendor_id）按供应商ID分配给供应商（ID、姓名）
每个员工 ID 至少有 2 个供应商。
然而，一个供应商对所有员工都是一样的——“ABC”
我需要一份未向供应商 ABC 支付报酬的员工名单。
例如：

Employee Vendor Month Total_amount
123     ABC     Jan 150
123     DEF     Jan 200
456     ABC     Jan 150
456     XYZ     Jan 250
123     DEF     Feb 200
456     ABC     Feb 150
456     XYZ     Feb 250

我的结果应该是二月份的 Employee_ID 123，因为当月没有向供应商 ABC 付款。

Answer 1

SQL小提琴

Oracle 11g R2 架构设置：

CREATE TABLE table_name ( Employee, Vendor, Month, Total_amount ) AS
SELECT 123, 'ABC', 'Jan', 150 FROM DUAL UNION ALL
SELECT 123, 'DEF', 'Jan', 200 FROM DUAL UNION ALL
SELECT 456, 'ABC', 'Jan', 150 FROM DUAL UNION ALL
SELECT 456, 'XYZ', 'Jan', 250 FROM DUAL UNION ALL
SELECT 123, 'DEF', 'Feb', 200 FROM DUAL UNION ALL
SELECT 456, 'ABC', 'Feb', 150 FROM DUAL UNION ALL
SELECT 456, 'XYZ', 'Feb', 250 FROM DUAL;

查询 1 ：

WITH EVA( Employee, Vendor, Total_Amount ) AS (
  SELECT DISTINCT
         Employee,
         Vendor,
         Total_Amount
  FROM   table_name
),
Months ( Month ) AS (
  SELECT DISTINCT MONTH FROM table_name
)
SELECT Employee, Vendor, Month, Total_Amount
FROM   EVA CROSS JOIN Months
MINUS
SELECT Employee, Vendor, Month, Total_Amount
FROM   table_name

结果：

| EMPLOYEE | VENDOR | MONTH | TOTAL_AMOUNT |
|----------|--------|-------|--------------|
|      123 |    ABC |   Feb |          150 |