join sql查询的单行结果

nfs0ujit 于 2021-06-17 发布在 Mysql

关注(0)|答案(2)|浏览(445)

我有一个sql查询：

SELECT p.id, p.firstname, p.lastname, p.emailcollected, p.phone, e.accountid, e.accounttype
FROM player p
JOIN bankaccountinfo e ON p.id = e.playerid
WHERE ( ( p.createtime > 0 AND p.createtime < 2000000000 ) OR
        ( p.updatetime > 0 AND p.updatetime < 200000000000000 ) )
  AND e.accounttype IN ( 5002,5003 ) ;

此返回结果在2行中有2个枚举类型的帐户类型：

+--------------+-----------+----------+----------------+------------+---------------+-------------+
| id           | firstname | lastname | emailcollected | phone      | accountnumber | accounttype |
+--------------+-----------+----------+----------------+------------+---------------+-------------+
|            9 | dineshND  | NineND   |     1536064455 | 5175761111 | 102323        |        5002 |
|            9 | dineshND  | NineND   |     1536064455 | 5175761111 | 102324        |        5003 |
+--------------+-----------+----------+----------------+------------+---------------+-------------+

但我希望accountnumber以单行形式显示，即savingaccountnumber和checkingaccountnumber基于accounttype。
预期结果：

+--------------+-----------+----------+----------------+------------+---------------------+-----------------------+
| id           | firstname | lastname | emailcollected | phone      | savingaccountnumber | checkingaccountnumber |
+--------------+-----------+----------+----------------+------------+---------------------+-----------------------+
|            9 | dineshND  | NineND   |     1536064455 | 5175761111 | 102323              |            102324     |
+--------------+-----------+----------+----------------+------------+---------------------+-----------------------+

accounttype为5003时保存AccountNumber列
AccountType为5002时检查AccountNumber列
mysql版本：mysql ver14.12 distrib 5.0.51a，适用于使用readline 5.2的debian linux gnu（i486）

sql mysql Join select

来源：https://stackoverflow.com/questions/53764173/single-row-result-of-join-sql-query

2条答案

按热度按时间

x8goxv8g1#

从您的样本数据和预期结果，您可以尝试使用条件加重函数

SELECT id,
    firstname,
    lastname,
    emailcollected,
    phone,
    MAX(CASE WHEN accounttype = 5003 THEN accountid END) savingaccountnumber,
    MAX(CASE WHEN accounttype = 5002 THEN accountid END) checkingaccountnumber
FROM (
    SELECT p.id, p.firstname, p.lastname, p.emailcollected, p.phone, e.accountid, e.accounttype
    FROM player p
    JOIN bankaccountinfo e ON p.id = e.playerid
    WHERE ( ( p.createtime > 0 AND p.createtime < 2000000000 ) OR
            ( p.updatetime > 0 AND p.updatetime < 200000000000000 ) )
      AND e.accounttype IN ( 5002,5003 ) 
) t1 
GROUP BY  id,firstname,lastname,emailcollected,phone

赞(0）回复(0）举报 2021-06-18

j7dteeu82#

你需要加入 bankaccountinfo 两次把东西排成一行：一次是支票，一次是储蓄。假设您（a）希望返回一行，即使缺少帐户记录，并且（b）在上定义了唯一键 bankaccountinfo 为了 playerid, accounttype :

SELECT
    p.id,
    p.firstname,
    p.lastname,
    p.emailcollected,
    p.phone,
    e1.accountid checkingaccountnumber,
    e2.accountid savingaccountnumber
FROM
    player p
LEFT JOIN
    bankaccountinfo e1
ON
    p.id = e1.playerid
    AND e1.accounttype = 5002
LEFT JOIN
    bankaccountinfo e2
ON
    p.id = e2.playerid
    AND e2.accounttype = 5003
WHERE
    (p.createtime > 0 AND p.createtime < 2000000000)
    OR (p.updatetime > 0 AND p.updatetime < 200000000000000)

不管怎样，温习一下join和in做了什么，以了解为什么会得到两个结果。

赞(0）回复(0）举报 2021-06-17

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join sql查询的单行结果

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