[英]Oracle LISTAGG case return distinct values
I am writing a ORACLE select statement with LISTAGG. 我正在用LISTAGG编写ORACLE select语句。 It works but when I was validating the data, I saw duplicates like 1:1,1:1,2:2,2:2.
它可以工作,但是当我验证数据时,我看到了1:1,1:1,2:2,2:2之类的重复项。
I verified that the database do have duplicate. 我验证数据库确实有重复项。 The query is for two tables in a one to many relationship.
查询是一对一关系中的两个表。 Below is a snippet of my query but I changed the column names etc..
以下是我的查询的摘要,但我更改了列名等。
how can I modified the following query to return unique values for each person? 如何修改以下查询以返回每个人的唯一值?
Thanks 谢谢
SELECT Table1.PERSON_ID,
Table1.FIRST_NAME,
Table1.MIDDLE_NAME,
Table1.LAST_NAME,
LISTAGG(case
when Table2.DESCRIPTION = '1' then '1:1'
when Table2.DESCRIPTION = '2' then '2:2'
when Table2.DESCRIPTION = '3' then '3:3'
when Table2.DESCRIPTION = '4' then '4:4'
when Table2.DESCRIPTION = '5' then '5:5'
when Table2.DESCRIPTION = '6' then '6:6'
when Table2.DESCRIPTION = '7' then '7:7'
when Table2.DESCRIPTION = '8' then '8:8'
when Table2.DESCRIPTION = '9' then '9:9'
else ''
end, ',')
WITHIN GROUP (ORDER BY Table2.DESCRIPTION )
FROM Table1
LEFT JOIN Table2
ON Table2.PERSON_ID = Table1.PERSON_ID
GROUP BY Table1.PERSON_ID,Table1.FIRST_NAME,Table1.MIDDLE_NAME, Table1.LAST_NAME
In Oracle, you need to do the DISTINCT
in a subquery: 在Oracle中,您需要在子查询中执行
DISTINCT
:
SELECT PERSON_ID, FIRST_NAME, MIDDLE_NAME, LAST_NAME,
LISTAGG(val, ',') WITHIN GROUP (ORDER BY DESCRIPTION )
FROM (SELECT DISTINCT Table1.PERSON_ID, Table1.FIRST_NAME, Table1.MIDDLE_NAME, Table1.LAST_NAME, Table2.Description
(case when Table2.DESCRIPTION = '1' then '1:1'
when Table2.DESCRIPTION = '2' then '2:2'
when Table2.DESCRIPTION = '3' then '3:3'
when Table2.DESCRIPTION = '4' then '4:4'
when Table2.DESCRIPTION = '5' then '5:5'
when Table2.DESCRIPTION = '6' then '6:6'
when Table2.DESCRIPTION = '7' then '7:7'
when Table2.DESCRIPTION = '8' then '8:8'
when Table2.DESCRIPTION = '9' then '9:9'
else ''
end) as val
FROM Table1 LEFT JOIN
Table2
ON Table2.PERSON_ID = Table1.PERSON_ID
)
GROUP BY PERSON_ID, FIRST_NAME, MIDDLE_NAME, LAST_NAME;
Assuming Table2
has PERSON_ID
as foreign key pointing to Table1
, what you need to do is to replace 假设
Table2
将PERSON_ID
作为指向Table1
外键,则需要替换
FROM Table1
LEFT JOIN Table2
ON Table2.PERSON_ID = Table1.PERSON_ID
with 与
FROM Table1
LEFT JOIN
(SELECT DISTINCT PERSON_ID, DESCRIPTION FROM Table2) T2
ON T2.PERSON_ID = Table1.PERSON_ID
and then change Table2
to T2
in LISTAGG()
(including in the WITHIN GROUP (ORDER BY ...)
clause!) 然后在
LISTAGG()
中将Table2
更改为T2
(包括WITHIN GROUP (ORDER BY ...)
子句!)
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