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如果发现其他插入，我已经提出了以下 SQL Server 查询以更新行

merge tblpermissions  as t
using (select cid, uid from tblpermissions) as s
on (t.cid = s.cid and t.uid=s.uid)
when not matched
THEN INSERT (cid, uid, [read], [write], [readonly], [modify], [admin]) VALUES ('1',   '1', 1, 1, 0, 1, 1) 
when matched 
THEN UPDATE SET [read]=1, write=1, readonly=0, modify=1, admin=1 ;

虽然它没有抛出任何错误，但它没有达到我的预期。表中没有记录，也没有插入新记录。

有什么更正吗？

编辑：考虑到您的建议，我已将其进一步修改如下，但没有任何预期结果-

MERGE INTO tblpermissions  as t
using (SELECT '1' AS cid, '1' AS uid FROM tblpermissions) as s
on (t.cid = s.cid and t.uid=s.uid)
WHEN NOT MATCHED 
THEN INSERT (cid, uid, [read], [write], [readonly], [modify], [admin])
VALUES  ('1', '1', 1, 1, 0, 1, 1) 
WHEN MATCHED
THEN UPDATE SET [read]=1, write=1, readonly=0, modify=1, admin=1 ;

编辑：请检查底部的评论，下面是对您的建议的改进查询，更不用说它不会按预期工作，因为它再次需要同一张表。

MERGE INTO tblpermissions  as t
using tblpermissions as s
on (t.cid = s.cid and t.uid=s.uid)
WHEN NOT MATCHED 
THEN INSERT (cid, uid, [read], [write], [readonly], [modify], [admin])
VALUES  ('1', '1', 1, 1, 0, 0, 1) 
WHEN MATCHED
THEN UPDATE SET [read]=1, write=1, readonly=0, modify=1, admin=1 ;

编辑：select-if found update-else insert alternative below -

$query = "SELECT * FROM ".SQL_PREFIX."permissions\n"
              ."WHERE cid='".$cid."' AND uid='".$uid."'";
    $sth = $this->dbh->query($query);
    $res = $sth->fetch();
    //print_r($res);var_dump($res);
    if(!$res || $res==null)
    {
        $query = "INSERT INTO ".SQL_PREFIX."permissions (cid, uid, [read], [write], [readonly], [modify], [admin])\n"
            ."VALUES ('$cid', '$uid', ".implode(", ", $values).")";
        if(!($sth = $this->dbh->query($query)))
            $this->db_error(__('Error inserting user permissions.'),
                $query);
    }else{
        $query = "UPDATE ".SQL_PREFIX."permissions SET ".implode(", ", $sets).";";
        if(!($sth = $this->dbh->query($query)))
            $this->db_error(__('Error updating user permissions.'),
                $query);
    }

编辑：以下是针对这种情况的 mysql 解决方案 -

插入 tblpermissions (cid, uid, [read], [write], [readonly], [modify], [admin]) 值 ('1', '1', 1, 1, 0, 0, 1) ON DUPLICATE KEY UPDATE [read]=1, write=1, readonly=0, modify=1, admin=1

它只是使用关键字 DUPLICATE KEY。还想再次强调，cid 和 uid 组合有唯一的键约束。所以 mysql 所做的是，首先它只是寻找我们试图插入的 cid 和 uid 的组合，如果找到更新它则插入新记录。

4

1 回答 1

2

因为源表和目标表相同，所以永远不会出现行不匹配的情况。正在更新 tblpermissions 上的所有行。

为了插入，源表（使用using定义）必须与目标表不同，例如以下示例：

merge tblpermissions  as t
using (select cid, uid from otherTable) as s
on (t.cid = s.cid and t.uid = s.uid)

merge tblpermissions  as t
using (select cid, uid from tblpermissions) as s
on (t.cid = s.cid + 1 and t.uid = s.uid + 1)

编辑：由于您使用的是常量值而不是从任何表中选择的结果，因此可能以下方法可以解决问题：

merge tblpermissions as t
using (select '1' cid, '1' uid, 1 [read], 1 [write], 0 [readonly], 0 [modify], 1 [admin]) s
on (t.cid = s.cid and t.uid = s.uid)
when matched 
    then update set [read] = s.[read], write = s.[write], readonly = s.[readonly], modify = s.[modify], admin = s.[admin]
when not matched
    then insert (cid, uid, [read], [write], [readonly], [modify], [admin]) values (s.cid, s.uid, s.[read], s.[write], s.[readonly], s.[modify], s.[admin]);

虽然我认为只插入一行合并是多余的，但执行以下操作会更容易：

if exists (select 1 from tblpermissions where cid = '1' and uid = '1')
update tblpermissions set [read] = 1, write = 1, readonly = 0, modify = 1, admin = 1 where cid = '1' and uid = '1'
else
    insert tblpermissions (cid, uid, [read], [write], [readonly], [modify], [admin]) VALUES ('1', '1', 1, 1, 0, 1, 1)

我认为 SQL Server 没有更短或更优雅的方式来执行此操作，这on duplicate与 MySQL 不同。

于 2013-05-09T14:17:55.490 回答