查询结果当临时表

查询结果当临时表

SELECT r.src_metric, r.expression, r.threshold, r.level, r.resgroup_code
FROM delta24_alarmrule r, (
		SELECT resgroup_code, src_metric, COUNT(*) AS c
		FROM delta24_alarmrule
		WHERE yn = 0
		GROUP BY resgroup_code, src_metric
	) temp
WHERE r.yn = 0
	AND r.resgroup_code = temp.resgroup_code
	AND r.src_metric = temp.src_metric
	AND temp.c = 2
ORDER BY r.resgroup_code, r.src_metric, r.level DESC

解释说明:

1. (
   SELECT resgroup_code, src_metric, COUNT(*) AS c
   FROM delta24_alarmrule
   WHERE yn = 0
   GROUP BY resgroup_code, src_metric
   ) temp 就是把内部临时查询结果当做表temp
2. 然后delta24_alarmrule表和临时表temp做内连接