Redshift：使用 DATE_TRUNC 生成重复行

Question

SELECT DATE_TRUNC('week', "date") as dates FROM dim_calendar dc WHERE "date" > '2019-01-01' AND "date" < CURRENT_DATE 正在创建重复项。

看到的结果示例：

A header
2019-01-07 00:00:00
2019-01-07 00:00:00
2019-01-07 00:00:00
2019-01-07 00:00:00
2019-01-07 00:00:00
2019-01-07 00:00:00
2019-01-07 00:00:00
2019-01-14 00:00:00
2019-01-14 00:00:00
2019-01-14 00:00:00
2019-01-14 00:00:00
2019-01-14 00:00:00
2019-01-14 00:00:00
2019-01-14

预期结果：

A header
2019-01-07 00:00:00
2019-01-14 00:00:00

我做错了什么？

Answer 1

可能你每周有好几次约会。您可以添加 DISTINCT:

SELECT DISTINCT DATE_TRUNC('week', "date") as dates FROM dim_calendar dc WHERE "date" > '2019-01-01' AND "date" < CURRENT_DATE