从不等于 Mysql Php 的字段中选择
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Select from where field not equal to Mysql Php
提问by Belgin Fish
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
我只是想知道我可以在 php 中执行什么样的 mysql 命令，它会从某个表中选择所有项目，其中 columna 不等于 x 且 columnb 不等于 x
Something like: select something from table where columna does not equal x and columnb does not equal x
就像是： select something from table where columna does not equal x and columnb does not equal x
Any ideas?
有任何想法吗？
回答by Jeffrey Blake
The key is the sql query, which you will set up as a string:
关键是 sql 查询，您将其设置为字符串：
$sqlquery = "SELECT field1, field2 FROM table WHERE NOT columnA = 'x' AND NOT columbB = 'y'";
Note that there are a lot of ways to specify NOT. Another one that works just as well is:
请注意，有很多方法可以指定 NOT。另一个同样有效的方法是：
$sqlquery = "SELECT field1, field2 FROM table WHERE columnA != 'x' AND columbB != 'y'";
Here is a full example of how to use it:
这是如何使用它的完整示例：
$link = mysql_connect($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
}
You can do whatever you would like within the above while loop. Access each field of the table as an element of the $row arraywhich means that $row['field1']will give you the value for field1on the current row, and $row['field2']will give you the value for field2.
你可以在上面的 while 循环中做任何你想做的事情。访问表的每个字段作为 的元素，$row array这意味着这$row['field1']将为您提供field1当前行$row['field2']的值，并将为您提供值field2。
Note that if the column(s) could have NULLvalues, those will not be found using either of the above syntaxes. You will need to add clauses to include NULLvalues:
请注意，如果列可以有NULL值，则使用上述任何一种语法都无法找到这些值。您需要添加子句以包含NULL值：
$sqlquery = "SELECT field1, field2 FROM table WHERE (NOT columnA = 'x' OR columnA IS NULL) AND (NOT columbB = 'y' OR columnB IS NULL)";
回答by Sayka
You can use like
你可以使用像
NOT columnA = 'x'
Or
或者
columnA != 'x'
Or
或者
columnA <> 'x'
And like Jeffly Bake's query, for including null values, you don't have to write like
就像 Jeffly Bake 的查询一样，对于包含空值，您不必像这样写
(NOT columnA = 'x' OR columnA IS NULL)
You can make it simple by
你可以通过
Not columnA <=> 'x'
<=>is the Null Safe equal to Operator, which includes results from even null values.
<=>是 Null Safe 等于 Operator，它包括偶数空值的结果。
回答by hazari zulkefli
Or can also insert the statement inside bracket.
或者也可以在括号内插入语句。
SELECT * FROM tablename WHERE NOT (columnA = 'x')
回答by Affan
select * from table where fiels1 NOT LIKE 'x' AND field2 NOT LIKE 'y'
//this work in case insensitive manner
//这项工作以不区分大小写的方式工作
回答by Prashant Tapase
$sqlquery = "SELECT field1, field2 FROM table WHERE columnA <> 'x' AND columbB <> 'y'";
I'd suggest using the diamond operator (<>) in favor of != as the first one is valid SQL and the second one is a MySQL addition.
我建议使用菱形运算符 (<>) 来代替 !=，因为第一个是有效的 SQL，第二个是 MySQL 的补充。
回答by KhabaNganba
You can use also
你也可以使用
select * from tablename where column1 ='a' and column2!='b';
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