MySQL分组-联合所有

我对报告有以下查询：

select @t := '' as 'Clave', @tf:='Inventario Físico' as 'Descripción', @t:= '' as 'Cantidad', @t:= '' as 'Precio Unitario' union all 
select @t:= '', @t:= '', @t:= '', @t:= '' union all 
(select cla, des, can, CAST(pl1*can as Decimal(10,2)) from inventario order by cla) union all 
select @t:= '', @t:='', @tnde := 'Número de Elementos: ', count(*) from inventario union all 
select @t:= '', @t:= '', @tne:= 'Suma total: $', sum(ppu) from inventario;

我需要第三个查询的“订购人”

select cla, des, can, CAST(pl1*can as Decimal(10,2)) from inventario order by cla

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就其本身而言，这行代码工作得非常完美，但是，当它位于联合体之间时，所有的信息都不是有序的。我怎样才能解决这个问题？谢谢。

union all

不保证数据符合子查询指定的顺序。您需要执行一个显式的orderby来获得该结果

这种方法添加了一个排序列以将组保持在一起。最后的

orderby

子句首先按

排序

排序，然后按用于排序第三个子查询的列排序：

(select @t := '' as Clave, @tf:='Inventario Físico' as Descripción,
        @t:= '' as "Cantida", @t:= '' as "Precio Unitario", 0 as ordering
) union all 
(select @t:= '', @t:= '', @t:= '', @t:= '', 1 as ordering) union all 
(select cla, des, can, CAST(pl1*can as Decimal(10,2)), 2 from inventario) union all 
(select @t:= '', @t:='', @tnde := 'Número de Elementos: ', count(*), 3 from inventario) union all 
(select @t:= '', @t:= '', @tne:= 'Suma total: $', sum(ppu), 4 from inventario)
order by ordering, clave;

我还将列别名上的单引号更改为双引号。我认为对字符串常量只使用单引号是一种很好的做法