YL,
(2) the rows in the table are
mysql> select * from tt;
+----+------+---------+
| id | name | options |
+----+------+---------+
|  1 | abc  | (1,2,3) |
|  2 | bbc  | (2,3,7) |
|  3 | cbc  | (3,1,7) |
+----+------+---------+
<snip>
>(4) My intention is a query like
>mysql> select id,name from tt where 7 in options;
>and expect
>+----+------+
>| id | name |
>+----+------+
>|  1 | abc  |
>|  2 | bbc  |
>|  3 | cbc  |
>+----+------+

>This is obviously wrong since column 'options' is of type varchar
>but look at the values of options, they are like arrays. So my question
>is how to fix query (4)? In other words, is there any function that
>i can use to get the result illustrated in (4)?
SQL doesn't do arrays, indeed keeping more than one value in one column breaks a basic rule of database design, but MySQL does have a column type for storing multiple values (http://dev.mysql.com/doc/mysql/en/set.html), so one solution available to you is to make your options column a SET column. If your options column values are ints, though, your database would be sounder and (not accidentally) your query would be much simpler if you were to project the options values out to a child table.

PB

-----

YL wrote:
My 1st question, can be understood after 3 steps below:
(1) Suppose we have a table defined as:
mysql> desc tt;
+---------+-------------+------+-----+---------+-------+
| Field   | Type        | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+-------+
| id      | int(11)     |      |     | 0       |       |
| name    | varchar(32) | YES  |     | NULL    |       |
| options | varchar(32) | YES  |     | NULL    |       |
+---------+-------------+------+-----+---------+-------+
(2) the rows in the table are
mysql> select * from tt;
+----+------+---------+
| id | name | options |
+----+------+---------+
|  1 | abc  | (1,2,3) |
|  2 | bbc  | (2,3,7) |
|  3 | cbc  | (3,1,7) |
+----+------+---------+
(3) the names of the matches of rows whoes id's are in an given array:
mysql> select name from tt where id in (2,3);
+------+
| name |
+------+
| bbc  |
| cbc  |
+------+
(4) My intention is a query like
mysql> select id,name from tt where 7 in options;
and expect
+----+------+
| id | name |
+----+------+
|  1 | abc  |
|  2 | bbc  |
|  3 | cbc  |
+----+------+

This is obviously wrong since column 'options' is of type varchar
but look at the values of options, they are like arrays. So my question
is how to fix query (4)? In other words, is there any function that
i can use to get the result illustrated in (4)?

----- Original Message ----- 
From: <SGreen@unimin.com>
To: "YL" <elim@pdtnetworks.net>
Cc: <mysql@lists.mysql.com>
Sent: Friday, September 02, 2005 2:29 PM
Subject: Re: 2 query questions


  
Answers blended in....

"YL" <elim@pdtnetworks.net> wrote on 09/02/2005 04:18:27 PM:

    
I've 2 basic questions. thanks for responses:

(1) Suppose i have a table with a varchar colum named options which
      
stores
    
option id's in the form
     "(id1, id2, ...., idk)", where id1,... are string representations
      
of
    
positive integers. Given an integer i,
     I want to fetch all ID's for the records in the table whoes
      
'options'
    
value when interprets as an array,
     contains integer i. What the query looks like?
      
I do not understand your question. SQL does not have arrays. It has rows
and columns and tables and lots of other things but no arrays. Programming
languages have arrays, not SQL. Are you trying to get some data and
populate an array with it? That's not completely a MySQL question, it's
more of a question about how to create arrays from strings in your
particular language. However, since there are MANY people on this list, I
am sure someone will know the answer so please explain what it is you are
doing, what language you are using to do it with, what your data looks
like (use "SHOW CREATE TABLE", and explain what you want your results to
look like.

    
(2) when using mysql command to query a value of type text, the
      
displayed
    
value always surrounded by lots
'-'s. My question is: How to get rid of those extras? (The following is
      
a
    
tail of display result:)
                          template = {
               b5 = resources/articles/_backups/subIndex_b5.template;
               gb = resources/articles/_backups/subIndex_gb.template;
           };
       };
   };


      
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When using the command line client, the headers, the data areas, and the
tails are each as wide as your data but they get "wrapped" to fit your
screen buffer. To make the wrapping effect go away in Windows, change the
Screen Buffer settings for your command shell window to something wide
enough to fit your results. One way you can get to the settings is by
right-clicking the window and picking "properties".

Shawn Green
Database Administrator
Unimin Corporation - Spruce Pine



    


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