I have multiple tables on specific database and each table similar to each other.
Table:
id series folder
1 Naruto 670
2 Naruto 671
3 Naruto 672
Each table has exact setup. Just series name changes. I want to pick up only 1 entry from series row and highest number from the folder row.
I will use this data to make it php array and use it for JSON data.
Here is my code:
'SELECT naruto.MAX(klasor), naruto.seri, one_piece.MAX(klasor), one_piece.seri, bleach.MAX(klasor), bleach.seri FROM `naruto` INNER JOIN `one_piece` INNER JOIN `bleach ON` LIMIT 1'
Use a GROUP BY clause like
select id,series,max(folder) as max_folder
from table1
group by series
Related
How to limit query to 100 if i have selected data from two tables.
But i want the limit 100 to only work on one of them.
SELECT c.* , p.*
FROM test c,test2 p
WHERE c.id=p.id_puf
LIMIT 100
But here is the tricky part(at least for me)
In table "test" ja hold names.
Structure:
ID, Name, Age
Table "test2" ja hold record of the persons and they are connected with user ID
Structure:
ID, connect(this is same as "test" id), numbers
Now every tabel row in "test" is unique
I want to get all the results for test but all the record from the "test2".
Here is how you would do it -- select the items from the first table you want and then join to the 2nd table.
SELECT *
FROM (
SELECT *
FROM test
LIMIT 100
) c
LEFT JOIN test2 p ON c.id=p.id_puf
Notice I'm using "modern" joins. The join style you were using is about 20 years out of date and is not as good. It is much clearer how to solve this problem if you are using modern joins (for example).
I am a beginner regarding SQL queries so I hope that someone can help me with this.
I have a table that has 2 columns that are called MID and jachtID.
What I need is the count of how many of the same jachtIDS there are with different MIDS attached to them like this:
MID jachtID
89 10
95 10
83 11
The result should look something like this:
MID jachtID count
89 10 2
95 10 2
83 11 1
And I need this for all of the rows
I have tried using
SELECT count(DISTINCT jachtID) FROM table
But this just gives me 1 big number and not the result that I need.
Any help would be appreciated.
You can try the following query:
SELECT
T.MID,
T.jachtID,
jT.total
FROM table T INNER JOIN
(
SELECT
jachtID,
COUNT(*) total
FROM table
GROUP BY jachtID
)AS jT
ON T.jachtID = jT.jachtID
First get count of each jachtID by the following query:
SELECT
jachtID,
COUNT(*) total
FROM table
GROUP BY jachtID
Then make an INNER JOIN between the main table and the above query and get the corresponding jatchtID count thereby.
You might be able to do this with some GROUP BY magic, but I'm not sure, since you want all the rows. Using a sub query will work, though.
SELECT
a.MID,
a.jachtID,
(SELECT count(b.jachtID) FROM table AS b WHERE b.jachtID= a.jachtID) AS `count`
FROM table AS a
How would I write a query that would select the name of a person (a column in the row) given that they have enough rows to meet all conditions?
For example, I have a database set up like so:
name permission_id
Bob 1
Bob 2
Jerry 3
Jerry 1
Jose 2
Billy 1
Billy 2
How would I only select the people that have permission id 1 and 2? In other words, I would like a query that checks every person by name to see if they have all the permissions requested.
In this example if I was to check for all users to who have permission 1 and 2 I should get Bob and Billy as a return value.
Here is my current query:
$this->db->select('center_user_permissions.id, center_users.first_name, center_users.last_name');
$this->db->from('center_user_permissions');
$this->db->where_in('permission_id', $permission_ids);
$this->db->join('center_users', 'center_users.center_id = center_user_permissions.center_id');
Currently this query returns anybody who has either permission id 1 or 2. I need it to be 1 AND 2. But I know I can't simply make two wheres because one particular row can't have both permission ids, but the query must check all rows for the specified ids.
I believe I would need a SELECT statement inside of my where? Can anybody tell me if I'm thinking correctly? Thanks.
You can use a in clause an an having for check that the user has both the permission
select name
from center_user_permissions
where permissions_id in (1,2)
group by name
having count(*) = 2
I'm not sure how to build this query in CodeIgniter, but you could INNER JOIN for each permission ID you want the user to have:
SELECT center_users.center_id, center_users.first_name, center_users.last_name
FROM center_users
INNER JOIN center_user_permissions AS p1 ON p1.center_id=center_users.center_id AND p1.permission_id=1
INNER JOIN center_user_permissions AS p2 ON p2.center_id=center_users.center_id AND p2.permission_id=2
You could check for more permissions by adding a INNER JOIN for each additional permission you wanted to require.
MySQL's GROUP BY and HAVING
Not user what kind of DB interface you're using in $this->db, but it may make things a little tricky. If I start with a raw SQL query:
SELECT
center_user_permissions.id,
center_users.first_name,
center_users.last_name
FROM center_user_permissions
LEFT JOIN center_users
ON center_users.center_id = center_user_permissions.center_id
WHERE center_user_permissions.permission_id in (1,2)
Group by name, where count of permission_id is > 1
This will group rows by first_name (so you'll only get one row for each unique name). Doing do allows you to run aggregate functions (SUM(), MAX(), COUNT()) against the rows that were "grouped" into a single row.
SELECT
center_user_permissions.id,
center_users.first_name,
center_users.last_name
FROM center_user_permissions
LEFT JOIN center_users
ON center_users.center_id = center_user_permissions.center_id
GROUP BY center_users.first_name
WHERE center_user_permissions.permission_id in (1,2)
HAVING COUNT(center_user_permissions.permission_id)>1
select distinct(name),.. as name from 'center_user_permissions',center_users where
center_users.center_id = center_user_permissions.center_id and permissions_id in (1,2)
substitute .. with your other fields and put in distinct the value that you want to be unique
Im having a brain fart as to how I would do this.
I need to select only the latest entry in a group of same id entries
I have records in an appointment table.
lead_id app_id
4 42
3 43
1 44
2 45
2 46 (want this one)
1 48
3 49 (this one)
4 50 (this one)
1 51 (this one)
The results I require are app_id 46,49,50,51
Only the latest entries in the appointment table, based on duplicate lead_id identifiers.
Here is the query you're looking for:
SELECT A.lead_id
,MAX(A.app_id) AS [last_app_id]
FROM appointment A
GROUP BY A.lead_id
If you want to have every columns corresponding to these expected rows:
SELECT A.*
FROM appointment A
INNER JOIN (SELECT A2.lead_id
,MAX(A2.app_id) AS [last_app_id]
FROM appointment A2
GROUP BY A2.lead_id) M ON M.lead_id = A.lead_id
AND M.last_app_id = A.app_id
ORDER BY A.lead_id
Here i simply use the previous query for a jointure in order to get only the desired rows.
Hope this will help you.
The accepted answer by George Garchagudashvili is not a good answer, because it has group by with unaggregated columns in the select. Select * with group by is simply something that should not be allowed in SQL -- and it isn't in almost all databases. Happily, the default version of the more recent versions of MySQL also rejects this syntax.
An efficient solution is:
select a.*
from appointment a
where a.app_id = (select max(a2.app_id)
from appointment a2
where a2.lead_id = a.lead_id
);
With an index on appointment(lead_id, app_id), this should be as fast or faster than George's query.
I think this is much more optimal and efficient way of doing it (sorting next grouping):
SELECT * FROM (
SELECT * FROM appointment
ORDER BY lead_id, app_id DESC
) AS ord
GROUP BY lead_id
this will be useful when you need all other fields too from the table without complicated queries
Result:
lead_id app_id
1 51
2 46
3 49
4 50
I have two MySql Tables as follows:
resource
-----------------------------------------------
id name group owner_id
-----------------------------------------------
1 MyResource1 hs 11
2 MyResource2 ms 24
3 MyResource3 ps 11
...
resource_access
-----------------------------------------------
id resource_id user_id
-----------------------------------------------
1 1 12
2 2 24
3 2 11
4 3 15
...
Now, the first table is a list of resources, of course, and their respective owners in the owner_id column. The second table is the result of "sharing" this resource with another user. The table resource_access may contain records with a user_id that is equivalent to the owner_id in a row of the resource_access as a result of messy cleanup from an owner exchange.
I simply want to get the id, name, and group of any resource that a user has access to, whether they are the owner or it has been shared with them. Here is my MySQL query for an example user (24):
SELECT resource.id, resource.name, resource.group
FROM `resource`
INNER JOIN resource_access ON (
resource.owner_id='24'
OR (
resource_access.user_id='24' AND
resource_access.resource_id=resource.id
)
)
Right now, it returns the id, name, and group for resource number 2 multiple times (like twelve). Is there a possible cause for this? I have tried LEFT and RIGHT joins and am getting the same result. There are many records in the resource table, but none with the id of 2. There are no duplicate rows in resource_access sharing the resource with the same user twice.
Thanks in advance.
Use:
SELECT DISTINCT resource.id, resource.name, resource.group
to remove duplicates.
The way an inner join conceptually works is that it produces a full cross-product between the two tables. This cross-product contains a row for each pair of rows in the input tables. Then it keeps the rows that match all the ON and WHERE conditions, and returns this as the result set. If there are multiple matching rows between the two tables, you'll get multiple rows in the result set.
If you were selecting columns from both tables, you would see that they're not actually the same row. They just have the same data from the resource table, but different data from the resource_access table. But you're not showing those latter columns in your result. Using DISTINCT merges all these rows in the result.
Because you are only selecting from the resource table, I would suggest putting the conditions in the where clause rather than using an explicit join:
SELECT r.id, r.name, r.group
FROM `resource` r
WHERE r.owner_id='24' or
EXISTS (select 1
from resource_access ra
where ra.resource_id = r.id and
ra.user_id = '24'
);
With this logic, the "join" cannot product duplicates.
Select the ownership of resources then union it to resources with access.
Resulting user_id column that is different from your WHERE RA.user_id value just means that resource was shared to them instead of them owning the resource. Hope this helps.
SELECT resource.name,resource.group,resource.owner_id AS user_id
FROM resource
WHERE resource.owner_id = '11'
UNION
SELECT R.name,R.group,R.owner_id AS user_id
FROM resource_access RA
LEFT JOIN resource R
ON (R.id=RA.resource_id)
WHERE RA.user_id = '11';