Distinct left table rows on a left join - mysql

Question

I need to distinct the left table rows on a left join.
Instead of this
| name | last name | phone |
|--------|-------------|---------|
| name1 | lastname1 | 1234567 |
|--------|-------------|---------|
| name1 | lastname1 | 2345678 |
|--------|-------------|---------|
| name2 | lastname2 | 3456789 |
I need this
| name | last name | phone |
|--------|-------------|---------|
| name1 | lastname1 | 1234567 |
| | | 2345678 |
|--------|-------------|---------|
| name2 | lastname2 | 3456789 |
I tried with a SELECT DISTINCT but without success...
I tried also a GROUP BY but it hides the second row

Answer 1

Mariano, followed you here from your WP post that got closed.
<?php
$results = your_sql_query_here();
$data = array();
foreach( $results as $result ) {
// Make a new array node for each name
if ( ! isset( $data[$result['name']] )
$data[$result['name']] = array();
$data[$result['name']][] = $result['phone'];
}
This will give you something like this
Array(
['name1'] => Array(
[0] => 5123451,
[1] => 5123452
),
['name2'] => Array(
[0] => 5123453,
[1] => 5123454
) )
You can then just do a for loop of your $data array, using the key as your name1 value.
Or store entire data sets
<?php
$results = your_sql_query_here();
$data = array();
foreach( $results as $result ) {
// Make a new array node for each name
if ( ! isset( $data[$result['name']] )
$data[$result['name']] = array();
$data[$result['name']][] = $result;
}
Now you will have access to all nodes, but grouped by name.
Array(
['name1'] => Array(
[0] => Array( 'name' => 'name1', 'phone' => 4165123, 'another_field' => 1 ),
[1] => Array( 'name' => 'name1', 'phone' => 4165157, 'another_field' => 0 ),
[1] => Array( 'name' => 'name1', 'phone' => 4225157, 'another_field' => 0 )
),
['name2'] => Array(
[0] => Array( 'name' => 'name2', 'phone' => 4165123, 'another_field' => 1 ),
[1] => Array( 'name' => 'name2', 'phone' => 4572321, 'another_field' => 1 ),
[1] => Array( 'name' => 'name2', 'phone' => 5235157, 'another_field' => 0 )
) )

Answer 2

You need GROUP_CONCAT:
This function returns a string result with the concatenated non-NULL values from a group.
So, your code will be:
SELECT name,
last_name,
GROUP_CONCAT(phone) AS phones
FROM table1
GROUP BY name, last_name;

Answer 3

Use GROUP_CONCAT() but beware of that fact it has the limit on character length of 1024 default,but can can be increased
SELECT name,
last_name,
GROUP_CONCAT(DISTINCT phone SEPARATOR ' ')
FROM table1
GROUP BY name, last_name
See fiddle Demo