我想用逗号分隔一个字段的值和 GROUP BY
Redshift中的另外两个字段。
样本数据。
table_schema table_name column_name
G1 G2 a
G1 G2 b
G1 G2 c
G1 G2 d
G3 G4 x
G3 G4 y
G3 G4 z
预期输出:
table_schema table_name column_name
G1 G2 a, b, c, d
G3 G4 x, y, z
我可以在MSSQL中这样做。
SELECT table_schema, table_name, column_name =
STUFF((SELECT ', ' + column_name
FROM your_table b
WHERE b.table_schema = a.table_schema AND b.table_name = a.table_name
FOR XML PATH('')), 1, 2, '')
FROM information_schema.tables t
INNER JOIN information_schema.columns c on c.table_name = t.table_name AND c.table_schema = t.table_schema
GROUP BY table_schema, table_name
而在PostgreSQL中则是:
SELECT table_schema, table_name, String_agg(column_name, ',')
FROM information_schema.tables t
INNER JOIN information_schema.columns c on c.table_name = t.table_name AND c.table_schema = t.table_schema
GROUP BY table_schema, table_name
但Redshift中并不包含 STRING_AGG
功能。
我不知道如何在Redshift中实现这个功能。
编辑
SELECT CUST_ID,
LISTAGG("ORDER", ', ')
WITHIN GROUP (ORDER BY "ORDER")
OVER (PARTITION BY CUST_ID) AS CUST_ID
FROM Table
ORDER BY CUST_ID
我的版本。
SELECT t.table_name, LISTAGG("column_name", ', ')
WITHIN GROUP (ORDER BY "column_name")
OVER (PARTITION BY t.table_name) AS table_schema
FROM information_schema.columns t
ORDER BY t.table_name
它给我以下错误。
0A000: Redshift表不支持指定的类型或函数(每条INFO消息一个)。
我不明白,因为我只是从一个节点中选择。
SELECT t.CUST_ID, c.orders
FROM Table t JOIN
(SELECT cust_id, LISTAGG("ORDER"::text, ', ')
WITHIN GROUP (ORDER BY "ORDER") as orders
FROM table t
GROUP BY cust_id
) c
ON t.cust_id = c.cust_id
ORDER BY CUST_ID;