I have next database
| ID | numbers |
|--------|------------|
| 1 | 1,2,3 |
| 2 | 4,5,6 |
| 3 | 2,3,4 |
To retrieve all rows where numbers holds a given number is easy:
SELECT * FROM mydb WHERE FIND_IN_SET(3, numbers)
This returns row 1 and 3
But now I want to pass an array/set of numbers and want to retrieve all entries where at least one number occurs in numbers, i.e. where the intersect of both sets is not empty
Something like:
SELECT * FROM mydb WHERE SET_INTERSECT('2,4', numbers)!=NULL
This should return all rows because every row holds 2 and/or 4.
The above doesn't work. Is this possible in mysql?
Thanks!
Why not use OR ?
SELECT * FROM mydb WHERE FIND_IN_SET(2, numbers) or FIND_IN_SET(4, numbers)
If you change the table structure to:
ID | NUMBERS
1 | 1
1 | 2
1 | 3
2 | 4
2 | 5
...
SELECT DISTINCT id FROM table WHERE numbers = 2 OR numbers = 4
/*or...*/
/*WHERE numbers IN (2, 4)*/
Related
Sorry for the previous question, it was unclear. I have edited it.
I have a MySql View that has 3 columns i.e. Schoolcode, No, and Gender. Below is the structure of the table
| Code| No |Gender|
+----------------------
| SLX | 12 | Female |
I want to transpose the above one row into 12 rows based on the value 12 in column "No" . I would like to repeat the code SLX 12 times and the gender "Female" 12 times
How do I do this in Mysql?
Any help is appreciated.
Create a table that will hold X numbers (X=the max of your column 'No')
+---+
| n |
+---+
| 1 |
| 2 |
| 3 |
| |
| X |
+---+
Your query is then
select code,gender
from
yourTable t
join numbers nb on nb.n<=t.no
I have 2 table and there's a column which contains comma separated value and I want to count all same value of that column, here's the sample table:
Client table
ID | Name | Procedure
1 | Joe | Samp1,Samp2
2 | Doe | Samp1,Samp2,Samp3
3 | Noe | Samp1,Samp2
Desire Output
Summary table ( For Procedure )
ID | NAME | COUNT
1 | Samp1 | 3
2 | Samp2 | 3
3 | Samp3 | 1
Now, do you have any idea or suggestion so i can make it happen ? like add new table or is this possible with single query ?
Try this query
SELECT LENGTH(COLUMN) - LENGTH(REPLACE(COLUMN, ',', '')) FROM TABLE_NAME
I have a MySQL table like below:
| ID | userIDs
---------------
| 1 | 4,3,5
| 2 | 2,3
| 3 | 1,2,3
I want to retrieve all the rows in which userIDs doesn't contain 1.
I tried
SELECT * FROM tablename WHERE 1 NOT IN (userIDs)
But it's not working.
Use FIND_IN_SET
SELECT * FROM tablename
WHERE find_in_set(1, userIDs) = 0
But actually you should rather change your table design. Never store multiple values in a single column!
I have table like:
user :
uid | course_id | subjects
---------------------------
1 | 1 | html,php
2 | 1 | java,html,sql
3 | 1 | java
4 | 1 | fashion,html,php,sql,java
I want to run a query which can return most liked subjects in query and then second most and so on...
For Example :
select * from user where subjects like '%java%' or '%php%' or '%html%';
this query will return data like this:
uid | course_id | subjects
---------------------------
2 | 1 | java,html,sql
3 | 1 | java
4 | 1 | fashion,html,php,sql,java
but i want output like this :
uid | course_id | subjects
---------------------------
4 | 1 | fashion,html,php,sql,java
2 | 1 | java,html,sql
1 | 1 | html,php
3 | 1 | java
so the most matched subjects 1st then 2nd most matched subjects and so on....
Is there any modification in my query so that i can get this type of sorted output.
Never, never, never store multiple values in one column!
Like you see now this will only give you headaches. Normalize your user table. Then you can select normally.
It should look like this
uid | course_id | subjects
---------------------------
1 | 1 | html
1 | 1 | php
2 | 1 | java
2 | 1 | html
2 | 1 | sql
3 | 1 | java
...
or better introduce an new table subjects and then make a mapping table called course_subjects
subject
id | name
------------
1 | html
2 | sql
3 | java
...
course_subjects
uid | course_id | subject_id
---------------------------
1 | 1 | 1
1 | 1 | 2
...
Based on the way you want your results, it looks like you want to order by the number of subjects (or tags) within subject. This can be accomplished by counting the number of , (commas).
The way to count the number of occurances of a character is to subtract the original length by the length when the character is removed.
Example:
SELECT *
FROM USER
WHERE subjects LIKE '%java%'
OR '%php%'
OR '%html%'
ORDER BY ( Length(subjects) - Length(Replace(subjects, ',', '')) ) DESC;
SQLFiddle: http://sqlfiddle.com/#!2/cc793/4
Result:
UID COURSE_ID SUBJECTS
4 1 fashion,html,php,sql,java
2 1 java,html,sql
3 1 java
Note:
As juergen says it is a bad idea to store multiple values in one column.
With MyISAM storage engine you can do match against.
The simplest example:
SELECT *,
MATCH (subjects) AGAINST ('java php html') AS relevance
FROM `user`
WHERE MATCH (subjects) AGAINST ('java php html')
ORDER BY relevance DESC
In MySQL 5.6 full-text search is available with InnoDB too but needs a bit extra to make it work. For more info checkout the following post: http://www.mysqlperformanceblog.com/2013/03/04/innodb-full-text-search-in-mysql-5-6-part-2-the-queries/
I've checked out a few of the stackoverflow questions and there are similar questions, but didn't quite put my fingers on this one.
If you have a table like this:
uid cat_uid itm_uid
1 1 4
2 1 5
3 2 6
4 2 7
5 3 8
6 3 9
where the uid column in auto_incremented and the cat_uid references a
category of relevance to filter on and the itm_uid values are the one
we're seeking
I would like to get a result set that contains the following sample results:
array (
0 => array (1 => array(4,5)),
1 => array (2 => array(6,7)),
2 => array (3 => array(8,9))
)
An example issue is - select 2 records from each category (however many categories there may be) and make sure they are the last 2 entries by uid in those categories.
I'm not sure how to structure the question to allow an answer, and any hints on a method for the solution would be welcome!
EDIT:
This wasn't a very clear question, so let me extend the scenario to something more tangible.
I have a set of records being entered into categories and I would like to select, with as few queries as possible, the latest 2 records entered per category, so that when I list out the contents of those categories, I will have at least 2 records per category (assuming that there are 2 or more already in the database). A similar query was in place that selected the last 100 records and filtered them into categories, but for small numbers of categories with some being updated faster than others can lead to having the top 100 not consisting of members from every category, so to try to resolve that, I was looking for a way to select 2 records from each category (or N-records assuming it's the same per-category) and for those 2 records to be the last entered. A date field is available to sort on, but the itm_uid itself could be used to indicate inserted order.
SELECT cat_uid, itm_uid,
IF( #cat = cat_uid, #cat_row := #cat_row + 1, #cat_row := 0 ) AS cat_row,
#cat := cat_uid
FROM my_table
JOIN (SELECT #cat_row := 0, #cat := 0) AS init
HAVING cat_row < 2
ORDER BY cat_uid, uid DESC
You will have two extra columns in the results, just ignore them.
This is the logic:
We sort the table by cat_uid, uid descending, then we start from the top and give each row a "row number" (cat_row) we reset this row number to zero whenever cat_uid changes:
---------------------------------------
| uid | cat_uid | itm_uid | cat_row |
| 45 | 4 | 34 | 0 |
| 33 | 4 | 54 | 1 |
| 31 | 4 | 12 | 2 |
| 12 | 4 | 51 | 3 |
| 56 | 6 | 11 | 0 |
| 20 | 6 | 64 | 1 |
| 16 | 6 | 76 | 2 |
| ... | ... | ... | ... |
---------------------------------------
now if we keep only the rows that have cat_row < 2 we get the results we want:
---------------------------------------
| uid | cat_uid | itm_uid | cat_row |
| 45 | 4 | 34 | 0 |
| 33 | 4 | 54 | 1 |
| 56 | 6 | 11 | 0 |
| 20 | 6 | 64 | 1 |
| ... | ... | ... | ... |
---------------------------------------
This is called an adjacent tree model or a parent-child tree model. It's one of the simplier tree model where there is only 1 pointer or 1 leaf. You would solve your query with a recursion or using a Self Join. Sadly MySQL doesn't support recursive queries, maybe it's working with prepared statements. I want to suggest you an Self Join. With a Self Join you can get all the rows from the right side and the left side with a special condition.
select t1.cat_uid, t2.cat_uid, t1.itm_uid, t2.itm_uid From t1 Inner Join t2 On t1.cat_uid = t2.cat_uid