mysql日期、时间戳转换函数

SELECT CURRENT_TIMESTAMP();
CURRENT_TIMESTAMP()  
---------------------
2020-04-27 17:22:49  

SELECT UNIX_TIMESTAMP(CURRENT_TIMESTAMP()); 
unix_timestamp(current_timestamp())  
-------------------------------------
                           1587979411


SELECT NOW(), CURRENT_TIMESTAMP();
now()                CURRENT_TIMESTAMP()  
-------------------  ---------------------
2020-04-27 17:23:43  2020-04-27 17:23:43  


SELECT FROM_UNIXTIME(1587979220);
from_unixtime(1587979220)  
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2020-04-27 17:20:20