Mysql with regular expression - php

Question

I have a query regarding regular expression.I have design a table which contain three column one column contain member ids which are separated by commas.I am showing you my table structure.Please follow
send_id member_id
1 1211,23,34
2 1,23
I want to select only send_id 2 data which contain member_id as 1.
this is the query that i am using
SELECT * FROM table WHERE column REGEXP '^[1]+$';
but this query giving me both row.Please help me.
With Regards
Rahul

Answer 1

Never store separate values in one column
Normalize your structure like
send_id member_id
1 1211
1 23
1 34
2 1
2 23
If you still want your regex, then it will be
SELECT * FROM t WHERE column REGEXP '(^|[^0-9])1([^0-9]|$)'

Answer 2

First, you should be normalizing your data so you're not in this horrible mess in the first place. Here's a good resource explaining normalization.
Second, I believe your problem lies with your regular expression. Try this instead:
SELECT * FROM table WHERE column REGEXP '^[1]$';
The regular expression you're using uses the [1]+ group. The + means it has to match [1] 1 or more times, hence why you're getting two rows instead of one. Removing the + means it will match [1] once.
However, that still won't fix your problem, as more than one row contains 1. This is why normalization is so important.

Answer 3

Having multiple values inside a column isn't a good practice for designing a DB.
You should normalize your data, i.e., put just one piece of atomic information inside each element of your table.
You can find more information regarding to this in Wikipedia:
http://en.wikipedia.org/wiki/Database_normalization

Answer 4

Like they have told you, perfect solution would be normalize your data, I think Alma Do Mundo answer explains it quite well.
If you want to use REGEXP anyway you have to take in account four approaches; id is the only one, id is the first, id is in the middle and id is at the end. I have use id=74 for the example:
SELECT * FROM table WHERE member_id REGEXP '(^74$|^74,|,74,|,74$)';

Answer 5

depending on your requirements, you should either normalize your data i.e. make 3 tables, one with the send ID, one with the member id, and one that combines the two, then you can link them up with INNER JOINS.
However, if you are going to do it that way, you can use a "WHERE member_id LIKE %1%" to pull in all the relevant fields. You'll have to use the application to filter the relevant records.
In any case, if you're not going to normalize the data you will have to use the front end to filter out the results.
An example of the inner join syntax would look like this
SELECT * FROM SendTable
JOIN Send_Member ON SendTable.send_id = Send_Member.send_id
JOIN Member ON Member.member_id = Send_Member.member_id
WHERE Member.member_id = 1;
where the schema looks like:
Sendtable:
send_Id (primary key)
...other fields
Send_Member:
send_id (primary key and foreign key to SendTable)
member_id (primary key and foreign key to member)
...any fields you might want that are relevant to the particular send table and member table link
Member:
member_id (primarykey)
...other fields