SQL SELECT查询列中的多个值和范围

Question

SQL SELECT query for multiple values and ranges in row data of a given column.

Problem description:

Server: MySQL
Database: Customer
Table: Lan
Column: Allowed VLAN (in the range 1-4096)

One row has data as below in the column Allowed VLAN :
180,181,200,250-499,550-811,826-mismatched

I need a SELECT statement WHERE the column Allowed VLAN includes a given number for instance '600' . The given number '600' is even one of the comma separated value or included in any of the ranges "250-499","550-811" or it is just the starting number value of "826-mismatched" range.

SELECT * WHERE `Allowed VLAN`='600' OR `Allowed VLAN` LIKE '%600%' OR (`Allowed VLAN` BETWEEN '1-1' AND '1-4096');

I could not figure it out how to deal with data ranges with WHERE Clause. I have solved the problem with PHP code using explode() split functions etc., but I think there are some SQL SELECT solutions.

I would be appreciated for any help.

Answer 1

I would highly recommend normalizing your data. Storing a comma-separated list of items in a single row is generally never a good idea.

Assuming you can make such a change, then something like this should work for you (although you could consider storing your ranges in different columns to make it even easier):

create table lan (allowedvan varchar(100));

insert into lan values 
  ('180'),('181'),('200'),('250-499'),('550-811'),('826-mismatched');

select *
from lan
where allowedvan = '600'
  or 
    (instr(allowedvan,'-') > 0 and 
     '600' >= left(allowedvan,instr(allowedvan,'-')-1) and
     '600' <= right(allowedvan,length(allowedvan)-instr(allowedvan,'-')) 
      )

SQL Fiddle Demo

This uses INSTR to determine if the value contains a range (a hyphen) and then uses LEFT and RIGHT to get the range. Do not use LIKE because that could return inaccurate results (600 is like 1600 for example).

If you are unable to alter your database, then perhaps look into using a split function (several posts on it on SO) and then you can do something similar to the above method.