您可以使用会话变量来获取行号。
在两个独立的派生表中，获取 Fristname ，和 Lastname （后者随机排列）。
把他们两个连在一起。自 Lastname 是随机排列的，你会得到不同的 Lastname 为了一个 Fristname .
这种方法将确保系统中没有重复项 Lastname 柱
mysql的所有版本：尝试以下操作（SQLFiddle演示）：

SELECT t3.Fristname,
       t4.Lastname 
    FROM ( 
           SELECT @rn1 := @rn1 + 1 AS rn1, 
                  t1.Fristname  
           FROM your_table AS t1 
           CROSS JOIN ( SELECT @rn1 := 0) AS rnt1 
         ) AS t3 
    INNER JOIN (
                 SELECT @rn2 := @rn2 + 1 AS rn2, 
                        t5.Lastname 
                 FROM 
                 ( 
                   SELECT t2.Lastname 
                   FROM your_table AS t2 
                   ORDER BY rand()
                 ) AS t5
                  CROSS JOIN ( SELECT @rn2 := 0) AS rnt2
                ) AS t4 ON t4.rn2 = t3.rn1

如果你不介意在姓氏一栏重复
您可以用一个简单的子查询来完成它，子查询的顺序和限制是随机的。
查询

SELECT
   Table1.Fristname
 , (SELECT Table11.Lastname FROM Table1 AS Table11 ORDER BY RAND() LIMIT 1) AS  Lastname
FROM 
 Table1

可能的结果

| Fristname | Lastname   |
| --------- | ---------- |
| user1     | lastname 3 |
| user2     | lastname 3 |
| user3     | lastname 3 |
| user4     | lastname5  |
| user5     | lastname4  |

db fiddle视图