SQL Join: Select rows with no match in second table - mysql

Question

I am trying to join two tables while still getting the results from table A even if there is no matching record in table B. I think the where clause is causing the problem but I can't seem to fix it.
SELECT a.id, a.title, a.validation, b.data
FROM client_option_detail AS a LEFT OUTER JOIN client_data AS b
ON a.id = b.client_option_detail_id
WHERE a.client_option_id = ?
AND (b.client_id IS NULL OR b.client_id = ?)
UPDATE:
database layout
client_option client_option_detail
------------- -------------------
id id
title
validation
client_option_id
client client_data
------- ------------
id client_id
client_option_detail_id
data
database sample:
client_option client_option_detail
------------- -------------------------------------------
id id | title | validation | client_option_id
------------- -------------------------------------------
1 1 | test1 | | 1
2 2 | test2 | | 1
3 | test3 | | 1
4 | test4 | | 2
client client_data (primary key - client_id + client_option_detail_id)
-------- -------------------------------------------
id client_id | client_option_detail_id | data
-------- -------------------------------------------
1 1 | 1 | data1
2 1 | 2 | data2
1 | 4 | data3
2 | 3 | data4
2 | 1 | data5
sample query:
SELECT a.id, a.title, a.validation, b.data
FROM client_option_detail AS a LEFT OUTER JOIN client_data AS b
ON a.id = b.client_option_detail_id
WHERE a.client_option_id = 1
AND (b.client_id IS NULL OR b.client_id = 1)
required output:
-------------------------------------------
id | title | validation | data
-------------------------------------------
1 | test1 | | data1
2 | test2 | | data2
3 | test3 | |

Answer 1

SELECT client_option_detail.id, title, validation, data
FROM client_option_detail LEFT OUTER JOIN client_data
ON client_option_detail.id = client_data.client_option_detail_id
It should be okey. I think is your where condition has some problem.
For example : client_option_detail.client_option_id = ?
,? is it contain all the id in client_option_detail ?

Answer 2

You do not need the AND (b.client_id IS NULL OR b.client_id = ?)
SELECT a.id, a.title, a.validation, b.data
FROM client_option_detail AS a
LEFT JOIN client_data AS b
ON a.id = b.client_option_detail_id
WHERE a.client_option_id = ?
output will be something like:
id title validation data
1 foo bar sample_data1
2 apple oranges null
3 try it sample_data2
Like in the sample output number 2, data will be null if there is not matched from table B and information from table A will still be shown
also, if you really wanted to filter based on specified client_id from B, then just put or on the last part like below. It means that if the data contains either specified client_id from B or if it has the specified client_option_id from A, then it will be retrieved.
SELECT a.id, a.title, a.validation, b.data
FROM client_option_detail AS a
LEFT JOIN client_data AS b
ON a.id = b.client_option_detail_id
WHERE a.client_option_id = ? OR b.client_id = ?
for more information, you might want to look at this post
UPDATE:
Try below codes for your update:
SELECT a.id, a.title, a.validation, b.data
FROM client_option_detail AS a
LEFT JOIN client_data AS b
ON a.id = b.client_option_detail_id AND b.client_id = a.client_option_id
WHERE a.client_option_id = 1
or this, i dont know which is right or the one that best suits for your needs but both yields same result based on your sample data:
SELECT a.id, a.title, a.validation, b.data
FROM client_option_detail AS a
LEFT JOIN client_data AS b
ON a.id = b.client_option_detail_id AND b.client_id = 1
WHERE a.client_option_id = 1
tried using SQLize:
I hope I got it right this time. Good luck