时间差 天数/小时/分钟/秒

UPDATE zc_repair
		SET maintain_finish_time ='2018-04-05 18:53:39',
        zc_repair_time_zosj=(

SELECT 
 CONCAT(TRUNCATE((UNIX_TIMESTAMP(maintain_finish_time)-UNIX_TIMESTAMP(equ_mal_time))/86400,0),'/',
TRUNCATE(MOD(UNIX_TIMESTAMP(maintain_finish_time)-UNIX_TIMESTAMP(equ_mal_time),86400)/3600,0),':',
TRUNCATE(MOD(UNIX_TIMESTAMP(maintain_finish_time)-UNIX_TIMESTAMP(equ_mal_time),3600)/60,0),':',
TRUNCATE(MOD(UNIX_TIMESTAMP(maintain_finish_time)-UNIX_TIMESTAMP(equ_mal_time),60),0)) FROM zc_repair WHERE zc_repair_id='325'
     
)
		WHERE
    zc_repair_id =325