English 中文(简体)
从一栏中选取价值与另一栏的数值相同
原标题:Don t select value from column identical to value of another column in SQL

我的表格有两栏:从<>id/strong>和,其中有相同的用户偶尔也在场。

我还有一个从这两栏中挑选所有女胎的落选箱。

我的问题是,下降选择了所有用户,但如果一个用户在两栏中,也重复使用。

如果用户在两个栏目中出现的话,我只想选择一个用户一次,并给予一个优先或高米(如果是?)。 这里是我迄今为止制定的法典:

$sql="
                            SELECT
                                DISTINCT u.".($config->realnames ? "name" : "username")." AS displayname,
                                u.id 
                            FROM
                                (#__users AS u
                            INNER JOIN
                                #__uddeim AS um
                            ON
                                u.id=um.fromid)
                            WHERE
                                um.toid=".(int)$myself."
                            AND
                                um.totrash=0
                            AND
                                `um`.`delayed`=0".$filter."
                            UNION ALL
                            SELECT
                                DISTINCT u.".($config->realnames ? "name" : "username")." AS displayname,
                                u.id
                            FROM
                                (#__users AS u
                            INNER JOIN
                                #__uddeim AS um
                            ON
                                u.id=um.toid)
                            WHERE
                                um.fromid=".(int)$myself."
                            AND
                                um.totrashoutbox=0".$filter."
                            AND um.systemflag=0";

WHAT I VE TRIED -

我用计票进行审判,但这项工作分两端:

if (count ($row->displayname > 1))
    echo "duplicate rows";
最佳回答

Try changing UNION ALL in You query to only UNION。 前者保留了两个数据集的所有数据集;后者消除了重复——这是一个缩短的<代码>。 UNION DISTINCT 。

问题回答

暂无回答




相关问题
SQL SubQuery getting particular column

I noticed that there were some threads with similar questions, and I did look through them but did not really get a convincing answer. Here s my question: The subquery below returns a Table with 3 ...

难以执行 REGEXP_SUBSTR

I m 查询Oracle 10g。 我有两张表格(样本数据见下文)。 i m 试图提取一些领域

SQL Query Shortcuts

What are some cool SQL shorthands that you know of? For example, something I learned today is you can specify to group by an index: SELECT col1, col2 FROM table GROUP BY 2 This will group by col2

PHP array callback functions for cleaning output

I have an array of output from a database. I am wondering what the cleanest way to filter the values is example array Array ( [0] => Array ( [title] => title 1 ...

OracleParameter and DBNull.Value

we have a table in an Oracle Database which contains a column with the type Char(3 Byte). Now we use a parameterized sql to select some rows with a DBNull.Value and it doesn t work: OracleCommand ...

Running numbers in SQL

I have a SQL-statement like this: SELECT name FROM users WHERE deleted = 0; How can i create a result set with a running number in the first row? So the result would look like this: 1 Name_1 2 ...

How to get SQL queries for each user where env is production

I’m developing an application dedicated to generate statistical reports, I would like that user after saving their stat report they save sql queries too. To do that I wrote the following module: ...