Sql在行之间拆分数

Question

如何在最后一行进行修正的行之间平均分割数字。假设数字是100，并且有11行。我将不得不将修正添加到最后一行。 注意：只要一行包含更正

，就不必是最后一行

select cost/count from table 将修正添加到最后一行除外。

有什么建议吗？

Answer 1

您可以使用简单的子查询执行此操作。例如

select floor(100 / (select count(*) from f)) as number_between_row_count;

然后，您可以设置用户变量并更新最后一行，例如;

set @number_between_row_count = 0;
select @number_between_row_count:=floor(100 / (select count(*) from f));
update f set bar = @number_between_row_count+1 order by id desc limit 1;
update f set bar = @number_between_row_count where bar is null;

我们的用户变量将保持计算（即：（100/5）= 20），因此将写入20。

http://dev.mysql.com/doc/refman/5.7/en/user-variables.html

修改

例如，我们有下表;

CREATE TABLE `33566497` (
  `number` int(11) DEFAULT NULL,
  `t` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

INSERT INTO `test`.`33566497` (`number`, `t`) VALUES ('1', NULL);
INSERT INTO `test`.`33566497` (`number`, `t`) VALUES ('2', NULL);
INSERT INTO `test`.`33566497` (`number`, `t`) VALUES ('3', NULL);
INSERT INTO `test`.`33566497` (`number`, `t`) VALUES ('4', NULL);
INSERT INTO `test`.`33566497` (`number`, `t`) VALUES ('5', NULL);
INSERT INTO `test`.`33566497` (`number`, `t`) VALUES ('6', NULL);
INSERT INTO `test`.`33566497` (`number`, `t`) VALUES ('7', NULL);
INSERT INTO `test`.`33566497` (`number`, `t`) VALUES ('8', NULL);
INSERT INTO `test`.`33566497` (`number`, `t`) VALUES ('9', NULL);
INSERT INTO `test`.`33566497` (`number`, `t`) VALUES ('10', NULL);
INSERT INTO `test`.`33566497` (`number`, `t`) VALUES ('11', NULL);

我们有11条记录。前10个需要t = 9，最后一个记录需要t = 10，然后我们才会运行;

set @number_between_row_count = 0;
select @number_between_row_count:=floor(100 / (select count(*) from `33566497`)); #calc the number (and round down so it's a whole number)
update `33566497` set t = @number_between_row_count+1 order by number desc limit 1; #update the last record to number + 1 because we need 10, not 9
update `33566497` set t = @number_between_row_count where t is null; #set the rest to 9

Answer 2

一个数字（任何数字，只需在集合中替换它）

select 100 / cast((select count(*) from #split) as float) as number_between_row_count

更新： 纠正：

drop table #split 
drop table #split2

create table #split (lineNumber float, valueTest float)

insert into #split values ('1','20'),('2','25'),('3','50'),
('4','22'),('5','100'),('6', '4'),('7','90'),('8','75'),('9','42'),('10','3'),('11','66')
update #split 
set valueTest = 100
select *, cast(valueTest / cast(round ((select count(*) from #split),0)as int)as int)as div into #split2 from #split 

update #split2
set div = (cast (div as int) + 
(cast (valueTest as int) % cast(div as int)))
where lineNumber = (select top 1 lineNumber  from #split2 order by lineNumber desc)

select * from #split2

给出：

LineNumber  ValueTest   div
1             100      9
2             100      9
3             100      9
4             100      9
5             100      9
6             100      9
7             100      9
8             100      9
9             100      9
10            100      9
11            100      10