如何使此SQL查询更有效？

Question

我有一个查询试图从多个表中提取数据，但是当我运行它时，它要花很长时间（很长一段时间我什至不能等待足够长的时间）。 我知道它效率极低，因此想获得一些有关如何更好地编写它的意见。 这里是：

SELECT 
        P.patient_name, 
        LOH.patient_id, 
        LOH.requesting_location, 
        LOH.sample_date,
        LOH.lab_doing_work,
        L.location_name, 
        LOD.test_code, 
        LOD.test_rdx,
        LSR.tube_type 
FROM 
        mis_db.dbo.lab_order_header AS LOH, 
        mis_db.dbo.patient AS P, 
        mis_db.dbo.lab_order_detail AS LOD, 
        mis_db.dbo.lab_sample_rule AS LSR,
        mis_db.dbo.location AS L
WHERE 
        LOH.requesting_location = '000839' AND
        LOH.lab_order_id = LOD.lab_order_id AND
        LOH.sample_date IN ('05/28/2015', '05/29/2015') 
        --LOH.patient_id = LOD.patient_id 
        --LOD.sample_date = LOH.sample_date 
ORDER BY 
        P.patient_name DESC 

Answer 1

试试这个（或类似的东西）

SELECT P.patient_name, 
    lo.patient_id, lo.requesting_location, 
    lo.sample_date, lo.lab_doing_work,
    l.location_name, d.test_code, d.test_rdx,
    d.tube_type 
FROM mis_db.dbo.lab_order_header lo 
    join mis_db.dbo.patient p on p.patient_id = lo.Patient_id
    join mis_db.dbo.lab_order_detail d on d.lab_order_id = lo.lab_order_id
    join mis_db.dbo.lab_sample_rule r on r.rule_id = lo.ruleId   -- ???? 
    join mis_db.dbo.location  l on l.locationid = lo.requesting_location  
WHERE lo.requesting_location = '000839' AND
     lo.sample_date IN ('05/28/2015', '05/29/2015') 
ORDER BY p.patient_name DESC 

Answer 2

我最终完成了以下工作，并能够获得想要的结果：

SELECT       LOH.patient_id,
               patient_name,
                         [mis_db_rpt].[common].[string_date_format](LOD.sample_date) AS
               [Draw Date],
               test_description,
               LOD.test_code,
               LOH.lab_doing_work,
               tube_type,
               L.short_name
FROM                   [mis_db].[dbo].[lab_order_header] 
               LOH
      INNER JOIN
                         [mis_db].[dbo].[lab_order_detail] 
               LOD 
      ON     LOH.lab_order_id = LOD.lab_order_id
      INNER JOIN
                         [mis_db].[dbo].[patient] 
               P 
      ON     P.patient_id = LOD.patient_id         
      INNER JOIN
                         [mis_db].[dbo].[sample_tube]
               ST
      ON     LOD.sample_id = ST.sample_id
      INNER JOIN
                         [mis_db].[dbo].[location] AS
               L
      ON     LOH.lab_doing_work = L.location_id
      INNER JOIN
                         [mis_db].[dbo].[lab_test] AS
               LT
      ON     LOD.test_code = LT.test_code         
WHERE       LOH.requesting_location = '000839' AND
LOD.sample_date IN ('05/28/2015', '05/29/2015') 
ORDER BY  LOD.sample_date,
                         patient_name,
                         LOD.patient_id,
                         test_description

Answer 3

我会尝试

1. 单击以在SSMS中运行估计的执行计划，然后查看它是否建议缺少任何索引。 我认为lo.requesting_location和sample_date上的非聚集索引可能有助于过滤器
2. 另外，在desc索引中，p。Patient_name可能有助于执行该命令。
3. 尝试将IN日期过滤器更改为“在'05 / 28/2015'和'05 / 29/2015之间”