PHP/MySQL - Trouble when trying to select two columns where id from table1 is equal to id from table2

Question

Here is my query:

$query = 'SELECT * extensa_econt_city as econt_city, extensa_econt_office as econt_office WHERE econt_city.city_id = econt_office.city_id';

I am trying to select all the rows from table extensa_econt_city and extensa_econt_office where city_id from extensa_econt_city is equal to city_id from extensa_econt_office .

Then when i get this information i have to create FORECH loop. It is important to be FORECH not while loop.

Here is my sample code:

<?PHP
foreach($results as $row){
   echo $row['econt_city.name'];
   echo $row['econt_office.name'];        
}
?>

In this foreach loop i have to select row name from extensa_econt_office and extensa_econt_city .

Structure:

I hope you understand what i am asking.

Can you help me out resolve this problem.

Thanks in advance!

Answer 1

I think this might do what you mean.

select 
    c.`city_id`,
    c.`post_code`,
    c.`type`,
    c.`name`,
    c.`name_en`,
    c.`zone_id`,
    c.`country_id`,
    c.`office_id`
    o.`FIELD_NAME` as 'ALIAS',
    o.`NEW_FIELD_NAME` as 'OTHER ALIAS'   
from `extensa_econt_city` c
left outer join `extensa_econt_office` o on o.`city_id`=c.`city_id`

Once the tables are aliased ( in this case the aliases are c & o ) you can select either all records using * ( unless there are duplicated names in which case you would get an error ) or, as above, select the desired fields directly in the query.

Once the query is set the FOREACH loop can select he record by the name / alias defined in the sql

Answer 2

I am trying to select all the rows from table extensa_econt_city and extensa_econt_office where city_id from extensa_econt_city is equal to city_id from extensa_econt_office... In this foreach loop I have to select row name from extensa_econt_office and extensa_econt_city .

    SELECT eec.name AS ee_city_name,
           eeo.name AS ee_office_name,
      FROM extensa_econt_city eec
 LEFT JOIN extensa_econt_office eeo ON eec.city_id = eeo.city_id

And in the PHP foreach loop, you can access the data like this:

<?php
foreach($results as $row){
   echo $row['ee_city_name'];
   echo $row['ee_office_name'];        
}

Answer 3

All you are looking for is the name column, not all columns (select *) from what you have shown. Don't drag down your system with wildcards as such (with select *). Also do an explicit join.

Here is a visual of my pretend schema, as I am not suggesting it is yours.

Do an explicit join, unlike your join in a where clause (that style is circa 1995)

Schema

create table extensa_econt_city
(   id int auto_increment primary key,
    city_id int not null,
    name varchar(100) not null
);
create table extensa_econt_office
(   id int auto_increment primary key,
    city_id int not null,
    name varchar(100) not null
);

insert extensa_econt_city(city_id,name) values (1,'eec name1'),(2,'eec name2'),(3,'eec name3');
insert extensa_econt_office(city_id,name) values (1,'EEO name1'),(2,'EEO name2'),(3,'EEO name3');

The Query

select eec.name as eec_name,eeo.name as eeo_name 
from extensa_econt_city eec 
join extensa_econt_office eeo 
on eeo.city_id=eec.city_id;

Results

+-----------+-----------+
| eec_name  | eeo_name  |
+-----------+-----------+
| eec name1 | EEO name1 |
| eec name2 | EEO name2 |
| eec name3 | EEO name3 |
+-----------+-----------+