Question

我一直在为我的问题寻找解决方案，我希望你帮助我我有一个有两列的表首先是一个名字，两个是一个小镇，我需要从Egpyt算起Sarah有多少重复，但这里是我需要的结果，如下表2所示可能

Name    town
Sarah   Egypt
John    Germany
Mick    France
Sarah   Egypt
Sarah   USA
John    Germany
Mick    France
John    Germany

Name    town    duplicate
Sarah   Egypt      1
John    Germany    1
Mick    France     1
Sarah   Egypt      2
Sarah   USA        1
John    Germany    2
Mick    France     2
John    Germany    3

Answer 1

您应该使用聚合函数count（*）和group by

select name, town, count(*) as duplicated 
from my_table 
group by  name, town

Answer 2

试试这个，

创建表格

create table test (name varchar(20), town varchar(20));

插入声明：

insert into test value('Sarah','Egypt');
insert into test values('John','Germany');
insert into test values('Mick','France');
insert into test values('Sarah','Egypt');
insert into test values('Sarah','USA');
insert into test values('John','Germany');
insert into test values('Mick','France');
insert into test values('Sarah','Egypt');

<强>查询：

set @x=1;
set @checkname='';
set @checktown='';
select name, town ,row_number
from ( select name, town, if(@checkname = name && @checktown = town,@x := @x + 1 ,@x := 1) as row_number,
@checkname := name, @checktown := town
from test
order by name, town 
) a

Answer 3

您可以使用此查询：

SET @row_number:=1;
SET @name:='';
SET @town:='';
    SELECT @row_number:=CASE WHEN @name=name and @town=town THEN @row_number+1 
      ELSE 1 END AS row_number, @name:=name, @town:=town
    FROM Table1 order by name, town;

检查SQL HERE

访问计数具有标准名人的记录数

3 个答案: