题
我张贴上周五( SQL多计数),并有一些反应。
尝试过今天实现这些,我不断收到同样的错误。
我的SQL代码现在是:
SELECT MBDDX_STUDY.STUDY_NAME,
COUNT(MBDDX_EXPERIMENT.STUDY_ID)
AS NUMBER_OF_EXPERIMENTS
FROM MBDDX_STUDY
INNER JOIN MBDDX_EXPERIMENT
ON MBDDX_STUDY.ID = MBDDX_EXPERIMENT.STUDY_ID
INNER JOIN (SELECT COUNT(MBDDX_TREATMENT_GROUP.GROUP_NO)
FROM MBDDX_TREATMENT_GROUP)
ON MBDDX_TREATMENT_GROUP.STUDY_ID = MBDDX_STUDY.ID
GROUP BY MBDDX_STUDY.STUDY_NAME
我不断收到错误:
ORA-00904: “MBDDX_TREATMENT_GROUP” “STUDY_ID”:无效的标识符
是因为它是内外面加入托架的,亦即出范围?我很新的SQL和不明白为什么它不会工作。我可以得到它的工作使用子查询选择(无连接),但我想也能够将工作与连接。
如果它的事项任何我使用蟾蜍为Oracle。
感谢。
解决方案
由于您使用联接的查询。提供一个名称该查询,并且是指这样的说法:
SELECT MBDDX_STUDY.STUDY_NAME
, COUNT ( MBDDX_EXPERIMENT.STUDY_ID )
AS NUMBER_OF_EXPERIMENTS
FROM MBDDX_STUDY
INNER JOIN MBDDX_EXPERIMENT
ON MBDDX_STUDY.ID = MBDDX_EXPERIMENT.STUDY_ID
inner JOIN ( SELECT study_id, COUNT ( MBDDX_TREATMENT_GROUP.GROUP_NO )
FROM MBDDX_TREATMENT_GROUP group by study_id ) AS my_query
ON my_query.STUDY_ID = MBDDX_STUDY.ID
GROUP BY MBDDX_STUDY.STUDY_NAME
其他提示
一方面,子查询必须具有一个别名。变化:
inner JOIN ( SELECT COUNT ( MBDDX_TREATMENT_GROUP.GROUP_NO )
FROM MBDDX_TREATMENT_GROUP )
ON MBDDX_TREATMENT_GROUP.STUDY_ID = MBDDX_STUDY.ID
到
inner JOIN ( SELECT COUNT ( MBDDX_TREATMENT_GROUP.GROUP_NO )
FROM MBDDX_TREATMENT_GROUP ) as CountAlias
ON MBDDX_TREATMENT_GROUP.STUDY_ID = MBDDX_STUDY.ID
第二件事是,你必须包括您计划使用的所有列。目前,子查询只选择一个数,但ON
条款引用STUDY_ID
。可以通过包括在子查询中选择列表STUDY_ID
,像修复:
inner JOIN (
SELECT STUDY_ID
, COUNT(MBDDX_TREATMENT_GROUP.GROUP_NO) as GroupCount
FROM MBDDX_TREATMENT_GROUP) as CountAlias
ON MBDDX_TREATMENT_GROUP.STUDY_ID = MBDDX_STUDY.ID
现在在这之后,你会打等问题,但我希望这将让你开始。
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