full join ，left join ，right join，inner join

時間 2020-12-06

標籤 spa code blog class join background 欄目 SQL 简体版

原文原文鏈接

full join ，left join ，right join，inner join

1、full join spa

----- full join
SELECT A.*, B.*
  FROM (SELECT 0 AS T1
          FROM DUAL
        UNION
        SELECT 1 AS T1
          FROM DUAL
        UNION
        SELECT 2 AS T1
          FROM DUAL
        UNION
        SELECT 3 AS T1 FROM DUAL) A
  FULL JOIN (SELECT 4 AS T1
               FROM DUAL
             UNION
             SELECT 3 AS T1 FROM DUAL) B
    ON A.T1 = B.T1

2、left join code

---- left join 

SELECT A.*, B.*
  FROM (SELECT 0 AS T1
          FROM DUAL
        UNION
        SELECT 1 AS T1
          FROM DUAL
        UNION
        SELECT 2 AS T1
          FROM DUAL
        UNION
        SELECT 3 AS T1 FROM DUAL) A
  LEFT JOIN (SELECT 4 AS T1
               FROM DUAL
             UNION
             SELECT 3 AS T1 FROM DUAL) B
    ON A.T1 = B.T1

----至關於

SELECT A.*, B.*
  FROM (SELECT 0 AS T1
          FROM DUAL
        UNION
        SELECT 1 AS T1
          FROM DUAL
        UNION
        SELECT 2 AS T1
          FROM DUAL
        UNION
        SELECT 3 AS T1 FROM DUAL) A,
       (SELECT 4 AS T1
          FROM DUAL
        UNION
        SELECT 3 AS T1 FROM DUAL) B
 WHERE A.T1 = B.T1(+)

3、rightjoin blog

---- right join 

SELECT A.*, B.*
  FROM (SELECT 0 AS T1
          FROM DUAL
        UNION
        SELECT 1 AS T1
          FROM DUAL
        UNION
        SELECT 2 AS T1
          FROM DUAL
        UNION
        SELECT 3 AS T1 FROM DUAL) A
  RIGHT JOIN (SELECT 4 AS T1
               FROM DUAL
             UNION
             SELECT 3 AS T1 FROM DUAL) B
    ON A.T1 = B.T1

----至關於

SELECT A.*, B.*
  FROM (SELECT 0 AS T1
          FROM DUAL
        UNION
        SELECT 1 AS T1
          FROM DUAL
        UNION
        SELECT 2 AS T1
          FROM DUAL
        UNION
        SELECT 3 AS T1 FROM DUAL) A,
       (SELECT 4 AS T1
          FROM DUAL
        UNION
        SELECT 3 AS T1 FROM DUAL) B
 WHERE A.T1(+) = B.T1

4、inner join class

---- inner join 

SELECT A.*, B.*
  FROM (SELECT 0 AS T1
          FROM DUAL
        UNION
        SELECT 1 AS T1
          FROM DUAL
        UNION
        SELECT 2 AS T1
          FROM DUAL
        UNION
        SELECT 3 AS T1 FROM DUAL) A
  INNER JOIN (SELECT 4 AS T1
               FROM DUAL
             UNION
             SELECT 3 AS T1 FROM DUAL) B
    ON A.T1 = B.T1

----至關於

SELECT A.*, B.*
  FROM (SELECT 0 AS T1
          FROM DUAL
        UNION
        SELECT 1 AS T1
          FROM DUAL
        UNION
        SELECT 2 AS T1
          FROM DUAL
        UNION
        SELECT 3 AS T1 FROM DUAL) A,
       (SELECT 4 AS T1
          FROM DUAL
        UNION
        SELECT 3 AS T1 FROM DUAL) B
 WHERE A.T1 = B.T1

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