MySQL grouping sort

http://blog.csdn.net/isoleo/article/details/50817976

1, add line number, B table has no substantive effect, just add line number , (Add a column ) an operation

Select @r:= @r+1 as Row_no, pkgname, coefficient, model_id
From A,
(select @r:=0) b
Limit 10;

2, generate the group ordinal, MySQL no row_number (), partition function function, the following statements are grouped according to MODEL_ID,

Select

@group_row: = Case When @model_id =a.model_id Then @group_row +1 Else 1 end as Group_row,

@model_id:=a.model_id as model_id,
A.coefficient,a.pkgname

From ' Getui_tag '. ' Model_coefficient ' A,

(Select @group_row: =1, @model_id: = ") b

Limit 100;

MySQL grouping sort