php MySQL，连接两列
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MySQL, Concatenate two columns
提问by Chandra Sekhar Biswal
There are two columns in a MySQL table: SUBJECTand YEAR.
MySQL 表中有两列：SUBJECT和YEAR。
I want to generate an alphanumeric unique number which holds the concatenated data from SUBJECT and YEAR.
我想生成一个字母数字唯一编号，其中包含来自 SUBJECT 和 YEAR 的连接数据。
How can I do this? Is it possible to use a simple operator like +?
我怎样才能做到这一点？是否可以使用像+?
回答by Mischa
回答by Shafiqul Islam
You can use php built in CONCAT() for this.
为此，您可以使用 CONCAT() 中内置的 php。
SELECT CONCAT(`name`, ' ', `email`) as password_email FROM `table`;
change filed name as your requirement
根据您的要求更改归档名称
then the result is
那么结果是
and if you want to concat same filed using other field which same then
如果您想使用其他相同的字段连接相同的文件，那么
SELECT filed1 as category,filed2 as item, GROUP_CONCAT(CAST(filed2 as CHAR)) as item_name FROM `table` group by filed1
then this is output
然后这是输出
回答by Vasanth
In php, we have two option to concatenate table columns.
在 php 中，我们有两个选项来连接表列。
First Option using Query
使用查询的第一个选项
In query, CONCATkeyword used to concatenate two columns
在查询中，CONCAT关键字用于连接两列
SELECT CONCAT(`SUBJECT`,'_', `YEAR`) AS subject_year FROM `table_name`;
Second Option using symbol ( . )
使用符号 ( . ) 的第二个选项
After fetch the data from database table, assign the values to variable, then using ( . ) Symboland concatenate the values
从数据库表中获取数据后，将值分配给变量，然后使用( . ) 符号并连接值
$subject = $row['SUBJECT'];
$year = $row['YEAR'];
$subject_year = $subject . "_" . $year;
Instead of underscore( _ ) , we will use the spaces, comma, letters,numbers..etc
我们将使用空格、逗号、字母、数字等代替下划线（_）
回答by Saravanan
$crud->set_relation('id','students','{first_name} {last_name}');
$crud->display_as('student_id','Students Name');
