mysql multi table foreign keys? - beginner - php

I have 2 tables,
Table1:
id, int1, int2, int3
john,1,2,4
tim,2,3,4
pete,1,3,4
Table2:
integer,blob
1,wins
2,backtickle
3,text
4,whatever
The query I want to use is given the id I want to get the blob data from table2 associated with each of the integer columns in table1.
What is the specific query I can use here?
Sample result I am looking for would be something like:
search John returns "wins","backtickle","whatever"
search pete returns "wins","text","whatever"
I think it has something to do with foreign keys, but not sure...beginner level please! With 1 table it would be SELECT * FROM table1 WHERE id="........" but not sure with the setup i have now given above.

The structure of your database does not look optimal. You're limiting yourself to 3 items per person, and you're using columns instead of rows in order to list them. What you actually have in your data is a many-to-many relationship between Table1 and Table2. What I'd recommend is using three tables:
Persons:
name, personid
john,1
tim,2
pete,3
PersonBlobs:
personid, blobid
1,1
1,2
1,4
2,2
2,3
2,4
3,1
3,3
3,4
Blobs:
blobid,blob
1,wins
2,backtickle
3,text
4,whatever
PersonBlobs would give you the many-to-many link between Persons and Blobs.
And then the query becomes:
select Blobs.blob
from Blobs inner join PersonBlobs on Blobs.blobid = PersonBlobs.blobid
inner join Persons on PersonBlobs.personid = Persons.personid
where Persons.name = 'John'

Related

Select rows where any of field's values matches values from array

I have a pretty complicated task. I need to select rows which match any of an array's value - BUT the field contains many comma-seperated values as well.
$teamlist = "25,26,27,28,29,30"
MYSQL-Row 1 = "26,29,31,35,36"
MYSQL-Row 2 = "30,31,32,36,39"
MYSQL-Row 3 = "31,35,36,37,38"
MYSQL-Row 4 = "23,26,29,30,31"
As result Rows 1,2 and 4 should be selected.
I tried something like:
mysqli_query($con,"SELECT * FROM user_meta WHERE team IN '".$ids."'");
But that only works if the fields only contain one id, not multiple. I am stuck. Any ideas?
Thanks!
You could pass your parameters as a derived table and then use find_in_set() to search the csv column:
select t.*
from mytable t
inner join (
select 25 team_id
union all select 26
union all select 27
...
) x on find_in_set(x.team_id, t.team)
This leaves you with the work of building the derived table from your application. In very recent versions of MySQL, the VALUES() statement makes the task a litte easier:
select t.*
from mytable t
inner join (values row(26),row(27), ...) x(team_id)
on find_in_set(x.team_id, t.team)
However, you should not be storing lists in a database columns. This is hurtful in many ways, as explained in this famous SO answer. You should be storing each value of the each list on a separate row.

MySQL Inner Join Returning Multiples of the Same Row

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';

pull combination of 2 tables from database

I need to pull combinations of 2 columns from two different tables from the same database.
ex:table1 has columns
Org_Id Org_Name
1001 company1
1002 company2
table2 has columns
Country_Id Country_Name
1 USA
2 uk
3 australia
4 canada
after creating combinations ,i need to create table 3 which hold the values of combinations...
table3 should have columns
org_name Country_Name
company1 usa
company2 uk
company2 usa
company1 canada
Note: Using joint we can display what ever we have in columns ,, but i need combinations of both the columns....
please help me this.....expecting your response asap....Thanks you all...
It's hard to tell from that how the 'combined' table should detect data, but normally that is done using views. Look into that.
Just noticed that in the manual there is actually an example that does pretty much what you described.
as described in example these two tables are not connected each other..
then you can directly take join without any joint condition ..
select Org_Name , Country_Name
from table1, table2
but as per practice this approach is not correct.. you should join tables with connected tables to show valuable result..
After you have figured how you want to join the tables, you could use INSERT ...SELECT
INSERT into table3(orgname,countryname) SELECT orgname,countryname from table1,table2;
You can create the new table and insert all the combinations in one fell swoop using SELECT INTO as follows:
SELECT org_Name, Country_Name
INTO table3
FROM table1, table2

Trying to display 2 tables data

I have 2 tables
Table name Dist.
NAME|Phone|ID
----------------
Oakley|555-555|1
Maui|666-666|2
lux|777-7777|3
Table name Patientacct.
Name|prescription|id|orderfrom
-------------------------------
bob|20-20|1|oakley
billy|15-20|2|Oakley, Maui
kim|20-20|3|Lux
I'm looking for a display like
Oakley
--------------------
Bob
Billy
Maui
------------------
Billy
Lux
--------------
kim
Trials so far
SELECT *
FROM `dist`
JOIN `patientacct` ON patientacct.dist LIKE CONCAT('%', `dist`.name ,'%')
GROUP BY `dist`.name
This showed only 1 dist
If I drop the group by example:
SELECT *
FROM `dist`
JOIN `patientacct` ON patientacct.dist LIKE CONCAT('%', `dist`.name ,'%')
I get the record twice so what I need is somewhere between the two. I'm extremely new to joins so be easy when explaining.
you must change your tables structure and you need to add a relation table with this values:
orders:
dist_id, patientacct_id PRIMARY_KEY(dist_id, patientacct_id)
First of all, please make the table structure relational. Have a primary auto_increment value in each table and use the primary key from the Dlist foreign key to Patientacct. This way, a simple join would fetch the record you have wanted.
Regarding the display, what do you mean you don't want record twice. Since you are using join, you will get two records for Oakley with the patient Bob and Billy. That's what you wanted and it would be like that by a simple join too in a relational table.

combining 2 tables in MySQL select statement

I know I can do joins but its not exactly what I want.
I'm making a live chat system that has 2 tables mainly: the main chat table (call it table a), and then a mod table (call this one table b). If a user gets suspended, messages reach over 100 for that channel, or they are over 1 week, the messages get moved from the main chat table to the mod table.
I store the ID of the chat messages as ID(primary) on the main chat table and as chatID on the mod table.
What I'm doing is making a separate page for my Mods and I want to be able to combine the two tables into 1 area but I want them to be ordered by their respective tables.
So lets say we had the following:
Main table ID's: 1,2,4
Mod table ID: 3
I want my results to show up 1,2,3,4 no matter which table the ID is in.
Any help is greatly appreciated!
Edit: I got the answer and this is what I used to do so:
SELECT ab.* FROM
((SELECT ID as table_id FROM a
WHERE roomID = 'newUsers' ORDER BY ID ASC)
UNION ALL
(SELECT chatID as table_id FROM b
WHERE roomID = 'newUsers' ORDER BY chatID ASC)) ab
ORDER BY ab.table_id
Use a UNION in a subselect.
SELECT ab.* FROM (
SELECT 1 as table_id, * FROM a
UNION ALL
SELECT 2 as table_id, * FROM b
) ab
ORDER BY ab.id
If you want the result of table A to appear before table B, change the query to:
SELECT ab.* FROM (
SELECT 1 as table_id, * FROM a
UNION ALL
SELECT 2 as table_id, * FROM b
) ab
ORDER BY ab.table_id, ab.id
Some background
UNION ALL will merge two tables resultsets into one resultset.
UNION will do the same but will eliminate duplicate rows.
This takes time and slows things down, so if you know there will be no duplicate records (or you don't care about dups) use UNION ALL.
See also: http://dev.mysql.com/doc/refman/5.5/en/union.html

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