SQL Left Join Return Latest Row - php

Question

Two tables, with a left join. For ease table 1 and table 2.
Table 1 contains a list of people and their current status, table 2 is all of their "invites". All im trying to do as part of the join is show in a list all the current "people" and then the LATEST invite status (from table 2) so return a single row from table 2.
I have everything working... but its duplicating for example if a person has had multiple invites it will put them twice on the list. I just want to limit it to
$sql = "SELECT table1.fieldname as table1fielname table2.fieldname [more fields]
FROM xxx
LEFT JOIN xxx on table1.sharedid=table2.sharedid
WHERE XXX LIMIT 1 ";`
Obvioulsy the limit 1 doesnt do what its supposed to. I have tried adding additional select statements in brackets but being honest it just breaks everything and im not an expert at all.

Answer 1

I'm not an expert too but I'll try. Have you tried to use DISTINCT?
For exemple:
SELECT DISTINCT column_name1,column_name2
FROM table_name; [...]
It normally delete double matches.
Here are the links:
http://www.w3schools.com/sql/sql_distinct.asp
https://www.techonthenet.com/oracle/distinct.php

Answer 2

Give example data. And use good table and column names. For example:
(this returns all rows that satisfy the join):
WITH people(ppl_id,ppl_name,status) AS (
SELECT 1,'Arthur','active'
UNION ALL SELECT 2,'Tricia','active'
), invites(ppl_id,inv_id,inv_date) AS (
SELECT 1,1, DATE '2017-01-01'
UNION ALL SELECT 1,2, DATE '2017-01-07'
UNION ALL SELECT 1,3, DATE '2017-01-08'
UNION ALL SELECT 2,1, DATE '2017-01-01'
UNION ALL SELECT 2,2, DATE '2017-01-08'
)
SELECT
*
FROM people
JOIN invites USING(ppl_id)
ORDER BY 1
;
ppl_id|ppl_name|status|inv_id|inv_date
1|Arthur |active| 1|2017-01-01
1|Arthur |active| 3|2017-01-08
1|Arthur |active| 2|2017-01-07
2|Tricia |active| 2|2017-01-08
2|Tricia |active| 1|2017-01-01
But we want only 'Arthur' with '2017-01-08' and 'Tricia' with '2017-01-08'.
With any database that supports ANSI 99, you could try with a temporary table containing the newest invitation date per "people id", and join that temporary table with the invitations table. We call that table newest_invite_date, and, apparently, it does what we expect it to do:
WITH people(ppl_id,ppl_name,status) AS (
SELECT 1,'Arthur','active'
UNION ALL SELECT 2,'Tricia','active'
), invites(ppl_id,inv_id,inv_date) AS (
SELECT 1,1, DATE '2017-01-01'
UNION ALL SELECT 1,2, DATE '2017-01-07'
UNION ALL SELECT 1,3, DATE '2017-01-08'
UNION ALL SELECT 2,1, DATE '2017-01-01'
UNION ALL SELECT 2,2, DATE '2017-01-08'
), newest_invite_date(ppl_id,inv_date) AS (
SELECT ppl_id,MAX(inv_date)
FROM invites
GROUP BY ppl_id
)
SELECT
people.ppl_id
, people.ppl_name
, people.status
, newest_invite_date.inv_date
FROM people
JOIN newest_invite_date USING(ppl_id)
ORDER BY 1
;
ppl_id|ppl_name|status|inv_date
1|Arthur |active|2017-01-08
2|Tricia |active|2017-01-08
Is this what you were looking for?
Happy playing ...
Marco the Sane