如何添加一个新列，将行数计算为序列号 [英] how can I add a new column which counts the number of rows as serial number

问题描述

record of
id  fare    commission  routecode   vehicle number  productcode date    time    driver  owner name
15  12345   123 4533    1   3344    2011-03-18  00:00:00    yasir   saleem
20  a   a   3433    1   2333    2011-03-25  00:00:00    yasir   saleem
36  11111   11111   3433    1   2333    2011-03-25  16:13:12    yasir   saleem
9   1233    123 3433    nk-234  2333    2011-03-24  00:00:00    siddiq  aslam
21  1200    120 4533    nk-234  7655    2011-03-24  00:00:00    siddiq  aslam
22  1200    133333  0987    nk-234  2333    2011-03-11  00:00:00    siddiq  aslam
23  10000   11  4533    nk-234  7655    2011-03-19  00:00:00    siddiq  aslam
25  122 12  0987    nk-234  2333    2011-03-11  00:00:00    siddiq  aslam
26  1000    100 3344    nk-234  7655    2011-03-11  00:00:00    siddiq  aslam
27  1000    100 3344    nk-234  2333    2011-03-10  00:00:00    siddiq  aslam
34  100 10  3344    nk-234  2333    2011-03-18  00:00:00    siddiq  aslam
35  100 10  3344    nk-234  2333    2011-03-02  00:00:00    siddiq  aslam
5   1000    100 1234    wq1233  3344    2011-03-10  22:30:00    waqas   sami
6   2222    22  1234    wq1233  3344    2011-03-17  22:30:00    waqas   sami
24  a   a   4533    PSS-1234    7655    2011-03-02  00:00:00    salman  salam
42633   145175                          

我想在 id 之前添加另一列来计算数量

I want to add another column before id which counts the number of

行.它应该从 1 开始，每行增加 1.

rows. It should start from 1 and increment by 1 for each row.

推荐答案

如果您的意思是在 SELECT 语句中:

If you mean in a SELECT statement:

说你的选择是

select * from tbl

变成

select @n := @n + 1 RowNumber, t.*
from (select @n:=0) initvars, tbl t

注意事项:

1. select @n:=0 用于将全局变量重置为0
2. @n := @n + 1 每行增加 1，从 1 开始.这一列被命名为RowNumber"

1. select @n:=0 is used to reset the global variable to 0
2. @n := @n + 1 increases it by 1 for each row, starting from 1. This column is named "RowNumber"

这篇关于如何添加一个新列，将行数计算为序列号的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！