I was working with a simple mysql table in php when I came across this problem and I am wondering if there is a solution to this.
The table holds a username and his locations in a comma separated format.
id|user|locations
------------------
1 |abc | A, B, C
------------------
2 |xyz | P, Q, R
I was wondering if there was any way to write a mysql query so that it would return me a user who has location as A.
Basically if one of the values among the comma separated values match, the record should be returned.
I know it is a better way to store them as separate records, but I was just curious if such a retrieval is possible.
Thanks in advance.
Ideally, you should consider normalizing the data so you are not storing the comma separated list.
But if you cannot alter the table structure, MySQL has a FIND_IN_SET() function that can be used to return the rows that match the value you want:
select id, user, locations
from yourtable
where find_in_set('A', locations)
See SQL Fiddle with Demo
We think
the following query may help you -
SELECT * FROM table WHERE column REGEXP '(^|,)A($|,)'
You can have a useful link in -
How to query comma delimited field of table to see if number is within the field
Related
I have searched but cannot find an answer that suits my needs specifically. I have two sets of data and need to compare a piece of the first (table 1 Description field) with a list (table two) and return the VIP codes for each interface/order.
The only identifier that is the same for any of the descriptions is the 9 digit order ID that ends in '003'. I need to compare this 9 digit string to the other table that will always start with the order ID but may contain other characters or numbers afterwards. I know a LIKE comparison will work for the second table but I cannot figure out how to strip the order numbers out of the description field.
UPDATE: Table 1 is a temporary table comparing the output of a router interface command. Table 2 is my static account database that has tens of thousands of entries that I do not want to compare to table one. This is why I do not just take table two and compare the order numbers to table one. I am specifically asking for help with a way to extract the 9 digit order ID from the description field of Table 1.
Table 1
Interface Description
Ge 1/0/1 blah_bla_123456003_blahlahlah
Ge 1/0/2 blah_blah_bla_234567003_blahahblh
Ge 1/0/3 b_bla_345678003_blhahblah
Ge 1/0/4 bh_blh_ba_456789003_lahlahbl
Table 2
Order ID VIP Code
123456003.0 Premier
234567003 Wholesale
345678003.6 Normal
456789003.23 Premier
Expected Results
Order* VIP Code
123456003 Premier
234567003 Wholesale
345678003 Normal
456789003 Premier
*(stripped from Description)
If you want to take the first 9 digits of ID from Table 2, you could use left(table2.id,9). It will return the 9 first (left) characters from that field.
Then you can use that with a LIKE (using the "%" wildcard) or using regular expressions.
Why not store the data you need in a dedicated column in each table? Make it a number column and index it, then you can do a very efficient JOIN using that column.
SELECT * FROM Table_1 LEFT JOIN Table_2 USING(common_index)
you can you something like this :
select TRUNCATE(tbl2.orderId,0) orderNum, tbl2.vipcode, tbl1.interface
from table2 tbl2 , table1 tbl1
WHERE tbl1.description like CONCAT('%',TRUNCATE(tbl2.orderId,0),'%');
i made a fiddle here
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
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]|$)'
First, you should be normalizing your data so you're not in this horrible mess in the first place. Here's a good resource explaining normalization.
Second, I believe your problem lies with your regular expression. Try this instead:
SELECT * FROM table WHERE column REGEXP '^[1]$';
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.
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
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$|^74,|,74,|,74$)';
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
I am quite new to PHP and MySQL, but have experience of VBA and C++. In short, I am trying to count the occurrences of a value (text string), which can appear in 11 columns in my table.
I think I will need to populate a single-dimensional array from this table, but the table has 14 columns (named 'player1' to 'player14'). I want each of these 'players' to be entered into the one-dimensional array (if not NULL), before proceeding to the next row.
I know there is the SELECT DISTINCT statement in MySQL, but can I use this to count distinct occurrences across 14 columns?
For background, I am building a football results database, where player1 to player14 are the starting 11 (and 3 subs), and my PHP code will count the number of times a player has made an appearance.
Thanks for all your help!
Matt.
Rethink your database schema. Try this:
Table players:
player_id
name
Table games:
game_id
Table appearances:
appearance_id
player_id
game_id
This reduces the amount of duplicate data. Read up on normalization. It allows you to do a simple select count(*) from appearances inner join players on player_id where name='Joe Schmoe'
First of all, the database schema you're using is terrible, and you just found out a reason why.
That being said, I see no other way then to first get a list of all players by distinctly selecting the names of players into an array. Before each insertion, you would have to check if the name is already in the array (if it is already in, don't add it again).
Then, when you have the list of names, you would have to run an SQL statement for each player, adding up the number of occurences, like so:
SELECT COUNT(*)
FROM <Table>
WHERE player1=? OR player2=? OR player3=? OR ... OR player14 = ?
That is all pretty complicated, and as I said, you should really change your database schema.
This sounds like a job for fetch_assoc (http://php.net/manual/de/mysqli-result.fetch-assoc.php).
If you use mysqli, you would get each row as an associative array.
On the other hand the table design seems a bit flawed, as suggested before.
If you had on table team with team name and what not and one table player with player names.
TEAM
| id | name | founded | foo |
PLAYER
| id | team_id | name | bar |
With that structure you could add 14 players, which point at the same team and by joining the two tables, extract the players that match your search.
I have a DB with several tables that contain basic, static ID-to-name data. 2 Columns only in each of these reference tables.
I then have another table that will be receiving data input by users. Each instance of user input will have it's own row with a timestamp, but the important columns here will contain either one, or several of the ID's related to names in one of the other tables. For the ease of submitting and retrieving this information I opted to input it as text, in json format.
Everything was going great until I realized I'm going to need to Join the big table with the little tables to reference the names to the ID's. I need to return the IDs in the results as well.
An example of what a few rows in this table might look like:
Column 1 | Column 2 | Timestamp
["715835199","91158582","90516801"] | ["11987","11987","22474"] | 2012-08-28 21:18:48
["715835199"] | ["0"] | 2012-08-28 21:22:48
["91158582","90516801"] | ["11987"] | 2012-08-28 21:25:48
There WILL be repeats of the ID#'s input in this table, but not necessarily in the same groupings, hence why I put the ID to name pairings in a separate table.
Is it possible to do a WHERE name='any-of-these-json-values'? Am I best off doing a ghetto join in php after I query the main table to pull the IDs for the names I need to include? Or do I just need to redo the design of the data input table entirely?
First of all:
Never, ever put more than one information into one field, if you want to access them seperately. Never.
That said, I think you will need to create a full N:M relation, which includes a join table: One row in your example table will need to be replaced by 1-N rows in the join table.
A tricky join with string matching will perform acceptably only for a very small number of rows, and the WHERE name='any-of-these-json-values' is impossible in your construct: MySQL doesn't "understand", that this is a JSON array - it sees it as unstructured text. On a join table, this clause comes quite naturally as WHERE somecolumn IN (1234,5678,8012)
Edit
Assuming your Column 1 contains arrays of IDs in table1 and Column 2 carries arrays of IDs in table2 you would have to do something like
CREATE TABLE t1t2join (
t1id INT NOT NULL ,
t2id INT NOT NULL ,
`Timestamp` DATETIME NOT NULL ,
PRIMARY KEY (t1id,t2id,`Timestamp`) ,
KEY (t2id)
)
(you might want to sanity-check the keys)
And on an insert do the following (in pseudo-code)
Remember timestamp
Cycle all permutations of (Column1,Column2) given by user
Create row
So for your third example row, the SQL would be:
SELECT #now:=NOW();
INSERT INTO t1t2join VALUES
(91158582,11987,#now),
(90516801,11987,#now);
I would like to select all matches from a commaseparated column in table2, where column could be like this: 0,1,2 OR 2,4,5 OR 2,5 OR 1,3,5 etc.
I have tried with:
SELECT * from table where 1,3,5 IN(SELECT commaseparated FROM table2) WHERE ..
But error on statement when using commas.
I've also tried using REGEXP but in my case i need to search for all matches within 1,3,5
How can i solve this one? :)
Can't do that in standard SQL. it's
WHERE singlevalue IN (list, of, values)
if you want to compare lists against lists, you should revamp your tables so they're properly normalized. Storing formatted data in a field basically negates the purpose of having a relational database - you can't establish relationships with the data if it's not in a format that allows relationships to be formed.
If those CSV lists were in sub-tables, you could do a very simple JOIN query to meet your specifications.