有时候,我们需要构造一个自然天的列作为temp表来join其他表数据,列出当月(或某几月)所有日期:
select to_char(tt.day, 'yyyy-mm-dd') as day
from (select generate_series(cast(to_char(current_date, 'yyyy-mm') || '-01' as date),
cast(cast(to_char(current_date, 'yyyy-mm') || '-01' as timestamp) + '1 MONTH' + '-1 d' as
date), '1 d') as day) as tt
order by day;
select to_char(tt.day, 'yyyy-mm-dd') as orderDate
from (select generate_series(cast(to_char(to_date('2018-07-11', 'YYYY-MM'), 'yyyy-mm') || '-01' as date),
cast(
cast(to_char(to_date('2018-08-12', 'YYYY-MM'), 'yyyy-mm') || '-01' as timestamp) + '-1 d'
as date), '1 d') as day) as tt
order by orderDate;