选择从哪里字段不等于Mysql Php [英] Select from where field not equal to Mysql Php

问题描述

我只是想知道什么样的mysql命令我可以在php中执行，将选择从某个表中的所有项目，其中columna不等于x和columnb不等于x

I'm just wondering what kind of mysql command i could execute in php that would select all items from a certain table where columna is not equal to x and columnb is not equal to x

类似：从表中选择一个列，其中columna不等于x，columnb不等于x

任何想法？

推荐答案

关键是sql查询，您将设置为字符串：

The key is the sql query, which you will set up as a string:

$sqlquery = "SELECT field1, field2 FROM table WHERE NOT columnA = 'x' AND NOT columbB = 'y'";

请注意，有很多方法可以指定NOT。另一个工作原理是：

Note that there are a lot of ways to specify NOT. Another one that works just as well is:

$sqlquery = "SELECT field1, field2 FROM table WHERE columnA != 'x' AND columbB != 'y'";

下面是如何使用它的完整示例：

Here is a full example of how to use it:

$link = mysql_connect($dbHost,$dbUser,$dbPass) or die("Unable to connect to database");
mysql_select_db("$dbName") or die("Unable to select database $dbName");
$sqlquery = "SELECT field1, field2 FROM table WHERE NOT columnA = 'x' AND NOT columbB = 'y'";
$result=mysql_query($sqlquery);

while ($row = mysql_fetch_assoc($result) {
//do stuff
}

你可以在上面的while循环中做任何你想要的访问表格的每个字段作为 $ row数组的一个元素这意味着 $ row ['field1'] 将为当前行提供 field1 的值， $ row ['field2'] 将为您提供 field2 的值。

You can do whatever you would like within the above while loop. Access each field of the table as an element of the $row array which means that $row['field1'] will give you the value for field1 on the current row, and $row['field2'] will give you the value for field2.

请注意，如果列可以有 NULL 值，那么将不会使用上述任何一种语法找到。包括 NULL 值：

Note that if the column(s) could have NULL values, those will not be found using either of the above syntaxes. You will need to add clauses to include NULL values:

$sqlquery = "SELECT field1, field2 FROM table WHERE (NOT columnA = 'x' OR columnA IS NULL) AND (NOT columbB = 'y' OR columnB IS NULL)";

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