Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
348 views
in Technique[技术] by (71.8m points)

sql - Generate serial number in mysql query

I have a table: student_marks

marks
-----
  44
  55
  64
  98
  76

Expected output:

serial_number|marks
--------------------
  1          | 44
  2          | 55
  3          | 64
  4          | 98
  5          | 76

Using mysql user defined variables, it could be done using query:

 set  @a:=0;select @a:=@a+1 serial_number, marks from student_marks;

Is there any way to achieve this in msyql without using user defined variables?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

Based on your reasons for not wanting to use user defined variables as wanting to avoid having 2 queries, one for inializing and one to use it you could use the following:

SELECT  @a:=@a+1 serial_number, 
        marks 
FROM    student_marks,
        (SELECT @a:= 0) AS a;

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...