Oracle listagg去重distinct的方式有哪些

在Oracle中，可以使用不同的方法来实现在使用LISTAGG函数时去重重复的值。以下是一些常用的方法：

使用子查询和ROW_NUMBER()函数：

SELECT LISTAGG(column_name, ',') WITHIN GROUP (ORDER BY column_name) AS resultFROM (SELECT column_name, ROW_NUMBER() OVER (PARTITION BY column_name ORDER BY column_name) rnFROM table_name)WHERE rn = 1;

使用GROUP BY子句：

SELECT LISTAGG(DISTINCT column_name, ',') WITHIN GROUP (ORDER BY column_name) AS resultFROM table_name;

使用CONNECT BY子句：

SELECT LISTAGG(column_name, ',') WITHIN GROUP (ORDER BY column_name) AS resultFROM (SELECT column_name, ROW_NUMBER() OVER (PARTITION BY column_name ORDER BY column_name) rnFROM table_name)START WITH rn = 1CONNECT BY PRIOR column_name = column_name AND PRIOR rn = rn-1;

这些方法可以根据具体需求选择合适的方式来去重重复的值。

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