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  • concat()用法

      

    SELECT school_code,`name`,phone from student WHERE login_name REGEXP 'ning$'LIMIT 10;

                

     concat()

    • SELECT CONCAT(school_code,`name`) from student WHERE login_name REGEXP 'ning$' LIMIT 10;

               

    • SELECT CONCAT(school_code,`name`,phone) from student WHERE login_name REGEXP 'ning$' LIMIT 10;(有一个字段是null,concat的结果是null)

              

      CONCAT_WS()

    • SELECT CONCAT_WS('-',school_code,NAME,login_name,phone) from student WHERE login_name REGEXP 'ning$' LIMIT 10;

               

    •  SELECT `name`,MIN(id) FROM student GROUP BY `name` HAVING COUNT(id) >=2 LIMIT 10;

              

     GROUP_CONCAT()

    • SELECT id,`name` from student WHERE `name`='刘媛媛' LIMIT 10;

                

    • SELECT NAME,GROUP_CONCAT(id) from student WHERE `name`='刘媛媛' LIMIT 10;

               

    •  SELECT NAME,GROUP_CONCAT(id) FROM student GROUP BY `name` HAVING COUNT(id) >=2 LIMIT 10;

              

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  • 原文地址:https://www.cnblogs.com/vanoraxnc/p/8981698.html
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