oracle 三表关联查询
左连接实现三表关联
表A---------------------------------关联第一张表B-----------------------关联第二张表c
1.语法
select * from 表名A left join 表B on A.columnX=B.columnM and A.columnY=B.columnN left join 表c on 表A=表c的id
2.应用场景
四张表 GJPT_BASY、GJZY_BASY、GJPT_BASY_ERROR、GJZY_BASY_ERROR
根据四张表,要求返回:医疗机构名称,医疗机构编号,总数,合格数和问题数
3.SQL实现
SELECT TEMP1.*, TEMP2.HEGESUM, TEMP3.TROUBLESUM
FROM (SELECT T1.YLNAME, T1.YLCODE, SUM(RS1) AS YLSUM--总数
FROM (SELECT COUNT(1) AS RS1,
HDSD00_11_118 AS YLNAME,
HDSD00_11_119 AS YLCODE
FROM GJPT_BASY
GROUP BY HDSD00_11_119, HDSD00_11_118
UNION ALL
SELECT COUNT(1) AS RS1,
HDSD00_12_133 AS YLNAME,
HDSD00_12_134 AS YLCODE
FROM GJZY_BASY
GROUP BY HDSD00_12_133, HDSD00_12_134
UNION ALL
SELECT COUNT(1) AS RS1,
HDSD00_11_118 AS YLNAME,
HDSD00_11_119 AS YLCODE
FROM GJPT_BASY_ERROR
GROUP BY HDSD00_11_119, HDSD00_11_118
UNION ALL
SELECT COUNT(1) AS RS1,
HDSD00_12_133 AS YLNAME,
HDSD00_12_134 AS YLCODE
FROM GJZY_BASY_ERROR
GROUP BY HDSD00_12_133, HDSD00_12_134) T1
GROUP BY T1.YLNAME, T1.YLCODE) TEMP1
LEFT JOIN (SELECT *
FROM (SELECT T2.YLNAME, T2.YLCODE, SUM(RS2) AS HEGESUM--合格数
FROM (SELECT COUNT(1) AS RS2,
HDSD00_11_118 AS YLNAME,
HDSD00_11_119 AS YLCODE
FROM GJPT_BASY
GROUP BY HDSD00_11_119, HDSD00_11_118
UNION ALL
SELECT COUNT(1) AS RS2,
HDSD00_12_133 AS YLNAME,
HDSD00_12_134 AS YLCODE
FROM GJZY_BASY
GROUP BY HDSD00_12_133, HDSD00_12_134) T2
GROUP BY T2.YLNAME, T2.YLCODE)) TEMP2
ON TEMP2.YLNAME = TEMP1.YLNAME
AND TEMP2.YLCODE = TEMP1.YLCODE
LEFT JOIN (SELECT *
FROM (SELECT T3.YLNAME, T3.YLCODE, SUM(RS3) TROUBLESUM--问题数
FROM (SELECT COUNT(1) AS RS3,
HDSD00_11_118 AS YLNAME,
HDSD00_11_119 AS YLCODE
FROM GJPT_BASY_ERROR
GROUP BY HDSD00_11_119, HDSD00_11_118
UNION ALL
SELECT COUNT(1) AS RS3,
HDSD00_12_133 AS YLNAME,
HDSD00_12_134 AS YLCODE
FROM GJZY_BASY_ERROR
GROUP BY HDSD00_12_133, HDSD00_12_134) T3
GROUP BY T3.YLNAME, T3.YLCODE)) TEMP3
ON TEMP3.YLNAME = TEMP1.YLNAME
AND TEMP3.YLCODE = TEMP1.YLCODE
WHERE TEMP3.YLCODE='41580781841010511A1001';
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本文来自博客园,作者:Marydon,转载请注明原文链接:https://www.cnblogs.com/Marydon20170307/p/9264551.html