mysql找到无与伦比的记录 [英] mysql finding unmatched record

问题描述

嗨frnds，



即时通讯我试图从2个表中找到无法比拟的记录我在下面尝试查询它工作正常但我需要找到多列匹配plz帮助



res = mysql_query（SELECT * FROM emp WHERE emp.roll_no NOT IN（SELECT emp_no FROM emp_old））;



同样我做了如下..

它有错误..



emp有rollno和name < br $> b $ b

emp_old有emp_no和名称



i需要找出这两个无与伦比的列



res = mysql_query（SELECT * FROM emp WHERE emp.roll_no AND emp.name NOT IN（SELECT emp_no AND name FROM emp_old））;

hi frnds,

im trying to find out unmatched records from 2 tables i had tried below query it works fine but i need to find for multiple column matching plz help

res = mysql_query("SELECT * FROM emp WHERE emp.roll_no NOT IN (SELECT emp_no FROM emp_old)");

similarly i had did as follows..
it has error..

emp has rollno and name

emp_old has emp_no and name

i need to find out for this two columns which are unmatched

res = mysql_query("SELECT * FROM emp WHERE emp.roll_no AND emp.name NOT IN (SELECT emp_no AND name FROM emp_old)");

推荐答案

你好，试试这些吧

1.

Hello, try these ones
1.

SELECT *
  FROM emp
 WHERE NOT EXISTS (SELECT emp_old.roll_no, emp_old.name
                     FROM emp_old
                    WHERE emp_old.roll_no = emp.roll_no AND
                          emp_old.name = emp.name)

2.

2.

SELECT emp.*
  FROM emp
  LEFT JOIN emp_old
    ON emp_old.roll_no = emp.roll_no AND
       emp_old.name = emp.name
 WHERE emp.name IS NULL

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