连接sql后数据返回重复

Question

我想加入两个临时表，但它会返回大量重复数据， 下面是我在加入表格之前得到的结果。

这是在我加入两个表之后，结果如下图所示

它使所有数据翻倍。

我使用这个sql加入这两个表。

`       SELECT * FROM(
            SELECT DISTINCT t1.hatch_num AS  hatch_num_1,t1.delay_code AS delay_code_1,t1.st_time + '-' + t1.ed_time AS time_1
            FROM #temp1 t1
        )as a

        CROSS JOIN
        (
            SELECT DISTINCT t2.hatch_num AS  hatch_num_2,t2.delay_code AS delay_code_2,t2.st_time + '-' + t2.ed_time AS time_2
            FROM #temp2 t2
        )as b`

我尝试使用内连接，左连接但返回相同的结果。

这里是＃temp1表sql，当我执行它时，它返回正确的数据。

      SELECT DISTINCT  t1.scn,CONVERT(DATE,t2.opr_st_dt_tm) as work_date,t2.hatch_num,
    t3.delay_code,REPLACE(CONVERT(varchar(5),t3.delay_st_dt_tm,108),':','')[time_start],
    REPLACE(CONVERT(varchar(5),t3.delay_ed_dt_tm,108),':','')[time_end]
    FROM ccostallysheet t1
    INNER JOIN ccostsitem t2 ON t2.master_id = t1.id
    INNER JOIN ccostsdelayitem t3 ON t3.master_id = t1.id
    WHERE t2.hatch_num = 'H1' AND t2.hatch_num IS NOT NULL
    GROUP BY t1.scn,t2.opr_st_dt_tm,t2.hatch_num,t3.delay_code,t3.delay_st_dt_tm,t3.delay_ed_dt_tm

这里是temp2 sql

SELECT DISTINCT t1.scn,CONVERT(DATE,t2.opr_st_dt_tm)as work_date,t2.hatch_num,
t3.delay_code,REPLACE(CONVERT(varchar(5),t3.delay_st_dt_tm,108),':','')[time_start],
REPLACE(CONVERT(varchar(5),t3.delay_ed_dt_tm,108),':','')[time_end]
FROM ccostallysheet t1
INNER JOIN ccostsitem t2 ON t2.master_id = t1.id
INNER JOIN ccostsdelayitem t3 ON t3.master_id = t1.id
WHERE t2.hatch_num = 'H2' AND t2.hatch_num IS NOT NULL
GROUP BY t1.scn,t2.opr_st_dt_tm,t2.hatch_num,t3.delay_code,t3.delay_st_dt_tm,t3.delay_ed_dt_tm

如何在不创建重复结果的情况下加入两个表？

Answer 1

您需要将表格加在一起。我猜延迟代码，所以像这样：

SELECT * FROM(
            SELECT DISTINCT t1.hatch_num AS  hatch_num_1,t1.delay_code AS delay_code_1,t1.st_time + '-' + t1.ed_time AS time_1
            FROM #temp1 t1
        )as a

        INNER JOIN
        (
            SELECT DISTINCT t2.hatch_num AS  hatch_num_2,t2.delay_code AS delay_code_2,t2.st_time + '-' + t2.ed_time AS time_2
            FROM #temp2 t2
        )as b ON a.delay_code_1 = b.delay_code_2

Answer 2

CROSS JOIN完全符合您的要求，这就是它的目的。另一方面，INNER JOIN应该只返回一些数据，但是你并没有告诉它要返回什么，所以它就像CROSS JOIN一样工作。 Simon向您举例说明如何告诉INNER JOIN要返回的内容，您需要使用ON后跟加入条件。由于您提供的信息不够充分，我不知道您的加入条件是什么，因此您必须自己解决这个问题，或者向我们提供有关您的两个表格和预期的更多详细信息。结果，所以我们可以帮助你。但是，根据您的描述，我觉得您正在寻找的内容可能是UNION，而不是JOIN。试试这个：

SELECT t1.hatch_num, t1.delay_code, t1.st_time + '-' + t1.ed_time AS time
FROM #temp1 t1

UNION

SELECT t2.hatch_num, t2.delay_code, t2.st_time + '-' + t2.ed_time AS time
FROM #temp2 t2

注意：您不需要在此使用DISTINCT，因为UNION会自动为您执行此操作。