Question

我有一张这样的表

id   name   amount
 1   fish    120
 1   meat    230
 2   meat    110
 2   fish    78
 1   salad   50
 3   meat    103
 3   salad    22
 2   salad    34

我想编写一个查询，将对名称进行分组并对其数量进行求和，但它应该限制为前两个id，因此按名称对项目进行分组，并将每个匹配的名称相加...这应该将其限制为前两个id 。只是id 1和2。离开id 3.注意。 ID是另一个表中的外键。

这是我尝试过的。但它不起作用

select name, sum(amount) from table1 group by amount, id order by id limit 2

这只在计算后输出2个结果

name   amount
fish   198
meat   443

我期待这样的事情

name   amount
fish   198
meat   340
salad  84

添加ID为1和2的项目数量，并按名称对其进行分组

Answer 1

select name, sum(amount)
from
  (SELECT id, name, amount,
       CASE WHEN @name=name THEN @rown:=@rown+1 ELSE @rown:=0 END as rn,
       @name:=name 
  FROM table1, (select @rown:=0, @name:='') s
  ORDER BY name, id
  ) sub
where rn<=1
group by name

输出

fish    198
meat    340
salad   84

Answer 2

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 }

Answer 3

您不希望限制总输出，但是您希望在它达到总和之前对其进行限制，以便您可以使用子查询。

select t1.name, sum(t1.amount)
from table1 t1 join
     (select tt1.id
      from table1 tt1
      group by id
      order by id
      limit 2
     ) t2
     on t1.id = t2.id
group by t1.name;

工作示例link

结果：

name    sum(t1.amount)

fish    198

meat    340

salad   84

Answer 4

前两个ID是什么？如果我认为你的意思是＆＃34;全球＆＃34;，那么：

var get_price = "1,200";
var result = get_price.replace(/[,]+/g, "").trim();
console.log(result);

Answer 5

删除LIMIT，仅GROUP BY name

SELECT Name, SUM(amount) AS Amount
FROM table1 
GROUP BY name 
ORDER BY id

输出

Name    Amount
fish    198
meat    443
salad   106

SQL小提琴：http://sqlfiddle.com/#!9/2a8868/7/0

Answer 6

我认为你可以使用这样的东西：

SELECT B.NAME, SUM(B.AMOUNT) AS AMOUNT
FROM (
      SELECT a.* ,
      @r:= CASE WHEN @g = a.NAME THEN @r+1 ELSE 1 END consecutive,
      @g:= a.NAME g    
      FROM DISHES a
      CROSS JOIN (SELECT @g:='', @r:=1 ) t1
      ORDER BY A.NAME, A.id
      ) B
      WHERE B.consecutive<=2
      GROUP BY B.NAME;

输出：

NAME    AMOUNT
fish    198
meat    340
salad   84

mysql group按名称查询，按ID排序，按id限制

6 个答案: