仅更改BIGINT类型的日期时间戳记的时间

Question

我想在stock_date中将时间设置为00:00:00而不更改年份，月份或日期，即如果日期表示形式为07-07-1994 10:45:23，我希望将其改为07-07-1994 00:00:00我环顾四周，但没有找到任何可能有所帮助的东西。以下是我的查询。谢谢。

SELECT stock_date   AS longDate, 
     'Tagged containers' AS transactionType, 
     tagged_cnt   AS quantity 
FROM RFID_INVENTORY_DAILY_STOCK 
WHERE grp_org_id = (SELECT GRP_ORG_ID 
        FROM GROUP_ORG_MAPPING 
        WHERE 
        grp_id =#group_id# 
        AND org_type = 'S' AND isactive=1 
        LIMIT 1) 
    AND stock_date >= #fromDate# 
    AND stock_date <= #toDate# 

Answer 1

使用date_trunc这样的：

SELECT date_trunc('day', current_timestamp); 

     date_trunc  
------------------------ 
2017-10-06 00:00:00+02 
(1 row)