sql - 选择不符合条件的项目

Question

有两个表JOB和WORKER。

工作表

• 乔比

工人表

• 工人ID
• JOBID（来自 JOB 表的 FK）
• 假期（“Y”或“N”）

通过这两个表，我想找到一个现在没有分配工人的工作列表。我进行了以下查询，但由于聚合函数SUM和CASE WHEN.

有比这更好的查询吗？

SELECT
    SUBQUERY.JOBID
FROM
(
    SELECT
        JOBID,
        SUM
        (
            CASE WHEN
                VACATION = 'N'
            THEN 1
            ELSE 0
            END
        ) NUM_WORKERS
    FROM
        JOB
    LEFT JOIN
        WORKER
    ON
        JOB.JOBID = WORKER.JOBID
    GROUP BY
        JOB.JOBID
) SUBQUERY
WHERE
    SUBQUERY.NUM_WORKERS = 0

Answer 1

Select * From job Where jobid not in（从工人中选择不同的jobid）

而已。

Answer 2

看看这里，希望对你有帮助

SELECT JOBID 
FROM JOB 
WHERE JOBID NOT IN (
    SELECT j.JOBID 
    FROM JOB j 
    JOIN WORKER w ON j.JOBID = w.JOBID
    WHERE w.VACATION = 'N'
    GROUP BY j.JOBID
)

Sqlfiddle 示例：示例

Answer 3

我会用这个：

SELECT j.jobid 
FROM job AS j
WHERE NOT EXISTS
      ( SELECT 1
        FROM worker AS w 
        WHERE w.vacation = 'N'
          AND w.jobid = j.jobid
      ) ;

或这个：

SELECT j.jobid 
FROM job AS j

EXCEPT

SELECT w.jobid
FROM worker AS w 
WHERE w.vacation = 'N' ;