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
1.3k views
in Technique[技术] by (71.8m points)

mysql - How to make limit offset dynamic using only (My)SQL

This code doesn't work

select pagenr into @offset from pages where id = 3;
select * from table1 limit @offset*10, 10;

What SQLcode do I need to use in order to get this kind of code to work
using only SQL!

Note that

SET SQL_SELECT_LIMIT = @count 

doesn't work because I'm mainly concerned with the offset, not the limit as such.

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)

From the MySQL 5.5 specification:

The LIMIT clause can be used to constrain the number of rows returned by the SELECT statement. LIMIT takes one or two numeric arguments, which must both be nonnegative integer constants, with these exceptions:

  • Within prepared statements, LIMIT parameters can be specified using ? placeholder markers.
  • Within stored programs, LIMIT parameters can be specified using integer-valued routine parameters or local variables as of MySQL 5.5.6.

So, inside a stored procedure, the following would work:

DECLARE offset bigint
SELECT pagenr * 10 INTO offset FROM pages where id = 3;
SELECT * FROM table1 LIMIT offset, 10;

Otherwise, you'll need to precompute the value and pass it in via the query. You should already know the page size and page number, so this shouldn't be difficult.


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

...