请教各位SQL 大牛,为啥这句SQL 语句超级慢呢(慢到超时的地步)

如何能优化一下呢?


SELECT TBL_WFM_TEMP.id, SUM(TBL_WFM_TEMP.time_length) AS Expr1,
SUM(TBL_HW_WFM_AGENT_LOG.LOGON_LENGTH) AS Expr2
FROM TBL_WFM_TEMP INNER JOIN
TBL_HW_WFM_AGENT_LOG ON LTRIM(RTRIM(TBL_WFM_TEMP.id))
= TBL_HW_WFM_AGENT_LOG.AGENT_ID
WHERE (LTRIM(RTRIM(TBL_WFM_TEMP.id)) IN ('0000', '0001', '0005', '0006', '0007',
'7512', '7515', '7516','信息中心部门', '研发部经理', '研发组长', '质检组长', '质检坐席zm')) AND
(TBL_WFM_TEMP.early_start_t >= '2007-10-22 00:00:00') AND
(TBL_WFM_TEMP.early_start_t <= '2007-10-29 23:59:59') AND
(TBL_HW_WFM_AGENT_LOG.LOGIN_TIME >= '2007-10-22 00:00:00') AND
(TBL_HW_WFM_AGENT_LOG.LOGIN_TIME <= '2007-10-29 23:59:59')
GROUP BY TBL_WFM_TEMP.id
ORDER BY TBL_WFM_TEMP.id