从Redshift中删除当前日期的秒数(PostgreSQL)

Question

在Amazon Redshift中,我希望将当前时间戳转换为0秒.那就是这样的:

2013-12-17 12:27:50

对此:

2013-12-17 12:27:00

我尝试过以下方法:

SELECT dateadd(second, -(date_part(second, getdate())), getdate());
ERROR:  function pg_catalog.date_add("unknown", double precision, timestamp without time zone) does not exist
HINT:  No function matches the given name and argument types. You may need to add explicit type casts.

SELECT dateadd(second, -cast(date_part(second, getdate()) as double precision), getdate());
ERROR:  function pg_catalog.date_add("unknown", double precision, timestamp without time zone) does not exist
HINT:  No function matches the given name and argument types. You may need to add explicit type casts.

SELECT getdate() - date_part(second, getdate());
ERROR:  operator does not exist: timestamp without time zone - double precision
HINT:  No operator matches the given name and argument type(s). You may need to add explicit type casts.

我可能错过了一个非常简单的方法!有人有什么建议吗？

Answer 1

使用该date_trunc()功能最简单,但只有在选择时才能使用:

SELECT date_trunc('minute', TIMESTAMP '2013-12-17 12:27:00');

您可以在将数据加载到redshift DB之前预处理数据,或者使用中间表然后使用INSERT INTO...SELECT语句:

INSERT INTO destination_table (
    SELECT date_trunc('minute', date_column), other_columns_here    
    FROM source_table
);