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PHP MySQL and joining two table results
Posted on 2016-09-17
Hi Experts,
I have two tables that rows are linked by the 'PersonRef' field.
Table 'person' example:
PersonRef FirstName LastName
12 Jim Smith
23 Alex Lewis
34 Linda Smith
Table 'person_meta' example:
PersonRef Field Value
12 Age 24
12 Title Mr
23 Age 24
23 Title Mr
34 Age 24
34 Title Mrs
I am looking for a sql query (mysqli_connect) that would return any person who is 'Age' = '24' and 'LastName' = 'Smith' but in an array with this format:
[0] => array('FirstName'=>'Jim','
[1] => array('FirstName'=>'Linda'
So basically searching the two tables and linking the data. Removing PersonRef 23 as they don't have a LastName Smith.
Any help would be gratefully received. I've been going round in circles with Joins.
I have two tables that rows are linked by the 'PersonRef' field.
Table 'person' example:
PersonRef FirstName LastName
12 Jim Smith
23 Alex Lewis
34 Linda Smith
Table 'person_meta' example:
PersonRef Field Value
12 Age 24
12 Title Mr
23 Age 24
23 Title Mr
34 Age 24
34 Title Mrs
I am looking for a sql query (mysqli_connect) that would return any person who is 'Age' = '24' and 'LastName' = 'Smith' but in an array with this format:
[0] => array('FirstName'=>'Jim','
[1] => array('FirstName'=>'Linda'
So basically searching the two tables and linking the data. Removing PersonRef 23 as they don't have a LastName Smith.
Any help would be gratefully received. I've been going round in circles with Joins.
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4 Comments
Active today
Formatting the result would be best put in a separate question. Get the query sorted first, and then worry about formatting the results after that. Try this query:
Note that unless you use left joins (which I haven't), you'll only get a row returned for a person when there exists both a title record in person_meta and an age record in person_meta
select FirstName, LastName, MetaTitle.Value Title, MetaAge.Value Age
from person
join person_meta MetaTitle on MetaTitle.PersonRef = person.PersonRef
join person_meta MetaAge on MetaAge.PersonRef = person.PersonRef
where MetaAge.Value = '24'
and LastName = 'Smith'
Note that unless you use left joins (which I haven't), you'll only get a row returned for a person when there exists both a title record in person_meta and an age record in person_meta
Active today
using a case/if statement within the join statement.
Select p.firstname,p.adtname,
(Get the title) as title,
(Get the age) as age
From person p join person_meta f on f.petsonref=p.personref
Where f.field='Age' and f.value=24 and p.lastname='Smith'
Group by p.lastname,p.firstname
This way if one is missing, you would still get the results.
Select p.firstname,p.adtname,
(Get the title) as title,
(Get the age) as age
From person p join person_meta f on f.petsonref=p.personref
Where f.field='Age' and f.value=24 and p.lastname='Smith'
Group by p.lastname,p.firstname
This way if one is missing, you would still get the results.
Active today
Here is the reference to case
https://dev.mysql.com/doc/refman/5.7/en/case.html
For age
(Case
When f.field='Age' then f.value
Else ''
End case) as Age
For Title
(Case
When f.field='Title' then f.value
Else ' '
End case) As Title
If mo title, you will get an empty string in the corresponding column, but if there is no Age, your query will return no values.
https://dev.mysql.com/doc/refman/5.7/en/case.html
For age
(Case
When f.field='Age' then f.value
Else ''
End case) as Age
For Title
(Case
When f.field='Title' then f.value
Else ' '
End case) As Title
If mo title, you will get an empty string in the corresponding column, but if there is no Age, your query will return no values.
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