等级语句导致查询运行非常缓慢

Question

我有以下查询。 “查询中的排名使查询运行了很长时间。我正在努力减少时间。 谁能帮我这个？谢谢

SELECT
                                 REC.INPATIENT_DATA_ID
                               , RANK() over (Partition by PATS.PAT_ENC_CSN_ID, MEAS.FLO_MEAS_ID order by RECORDED_TIME) 'VITALS_RANK' 
                               , MEAS.RECORDED_TIME
                               , PATS.PAT_ENC_CSN_ID
                               , PATS.PAT_ID
                               , PATS.CONTACT_DATE
                               , MEAS.FLO_MEAS_ID
                               , PATS.DEPARTMENT_ID
                               , PAT.IS_TEST_PAT_YN
                               , PATS.HOSP_DISCH_TIME
                               , PATS.HOSP_ADMSN_TIME
                         FROM CLARITY.DBO.IP_FLWSHT_REC  REC
                         LEFT OUTER JOIN CLARITY.DBO.PAT_ENC_HSP PATS ON PATS.INPATIENT_DATA_ID = REC.INPATIENT_DATA_ID 
                         LEFT OUTER JOIN CLARITY.DBO.CLARITY_DEP AS DEP ON PATS.DEPARTMENT_ID = DEP.DEPARTMENT_ID
                         LEFT OUTER JOIN CLARITY.DBO.PATIENT_3 PAT ON PAT.PAT_ID = PATS.PAT_ID  
                         LEFT OUTER JOIN CLARITY.DBO.IP_FLWSHT_MEAS MEAS ON REC.FSD_ID = MEAS.FSD_ID