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查找列值链

common-table-expression sql-server-2008-r2 tsql sql-server sql

MAK · 技术社区 · 7 年前

表:

create table tbl_test
(
    col1 int,
    col2 int
);

记录:

INSERT INTO tbl_test VALUES(111,112),
                            (112,113),
                            (113,114),
                            (114,111),
                            (115,116),
                            (117,118),
                            (118,119),
                            (111,130),
                            (120,121),
                            (122,123),
                            (123,111),
                            (124,111);

查询 :我想找到完整的链col1和col2的形式 111->112->113->114->111 (这是完整的链条,因为它从 111 最后是 一百一十一 )

预期输出2:

col1    col2
-------------
111     112
112     113
113     114
114     111

1 回复 | 直到 7 年前

gotqn user3521065 7 年前


   start value


   stop


   col01


   start

WITH DataSource AS
(
    SELECT col1
          ,col2
          ,0 as level
          ,ROW_NUMBER() OVER(ORDER BY Col1, col2) AS [groupID]
          ,0 as anchorMatched
          ,col1 as startValue
    FROM tbl_test
    WHERE col1 IN (SELECT MIN(col1) FROM tbl_test)
    UNION ALL
    SELECT A.col1
          ,A.col2
          ,level + 1
          ,B.[groupID]
          ,anchorMatched + CASE WHEN A.col1 = B.col2 AND A.col2 = B.startValue THEN 1 ELSE 0 END
          ,b.startValue
    FROM tbl_test A
    INNER JOIN DataSource B
        ON A.col1 = B.col2
    WHERE (anchorMatched = 0 AND A.col1 <> B.startValue)
)
SELECT *
FROM DataSource
WHERE groupID = 1;