Re: string->array question. ( 2 query questions)

[Peter Brawley]

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: <[EMAIL PROTECTED]> To: "YL" <[EMAIL PROTECTED]> Cc: <mysql@lists.mysql.com> Sent: Friday, September 02, 2005 2:29 PM Subject: Re: 2 query questions Answers blended in.... "YL" <[EMAIL PROTECTED]> 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; }; }; }; |--------------------------------------------------------------------------- -------------------------------------------- -------------------------------------------------------------------------- -- ------------------------------------------- -------------------------------------------------------------------------- -- ------------------------------------------- -------------------------------------------------------------------------- -- ------------------------------------------- -------------------------------------------------------------------------- -- ------------------------------------------- ----------------------------------------------------------+ 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 ---------------------------------------------------------------------------- ---- Checked by AVG Anti-Virus. Version: 7.0.344 / Virus Database: 267.10.18/86 - Release Date: 8/31/2005

No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.344 / Virus Database: 267.10.18/89 - Release Date: 9/2/2005


-- 
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe:    http://lists.mysql.com/[EMAIL PROTECTED]