mysql - 根据日期选择行

Question

我有两个表，任务和操作。 actions 有两列:created_at 和updated_at。任务有一个列started_at

我怎样才能做类似的事情

SELECT MAX( UNIX_TIMESTAMP( tasks.started_at ) ) AS started_at, action . * 
FROM tasks, action
WHERE UNIX_TIMESTAMP( action.created_at ) > started_at
OR UNIX_TIMESTAMP( action.updated_at ) > started_at

尝试选择created_at或updated_at大于MAX(tasks.started_at)的所有操作

Answer 1

SELECT * FROM actions 
WHERE created_at>(SELECT MAX(started_at) FROM tasks) OR
      updated_at>(SELECT MAX(started_at) FROM tasks)

不用担心性能，默认情况下MySQL应该缓存SELECT MAX(started_at) FROMtasks值。如果您有其他配置，请将 SQL_CACHE 添加到主查询:SELECT SQL_CACHE * FROM...