Postgres 日期操作

SELECT TO_CHAR(drmo.fiscal_period, 'YYYY-MM-01')    -- 日期截取到 1 号

SELECT date_trunc('year', contract_signing_time) AS year -- 日期按年月日截取

SELECT contract_signing_time-interval '1 month' -- 取上月 1 号

UPDATE dthouse_expense_real_erp
    SET
        year=CAST(SUBSTRING(expense_date,1,4) AS INTEGER),
        month=CAST(SUBSTRING(expense_date,6,2) AS INTEGER),
        expense_date_date=CAST(concat(expense_date,'-01') AS DATE)
​