How to join my tables with ID's that do not match - sql

Question

I have these tables:
payments
| id | src_account | dest_account | payment_value |
+----+-------------+--------------+---------------+
| 1 | xxxxxxxxxxx | yyyyyyyyyyyy | 200 |
client_account
| client_id | account_id |
+-----------+-------------+
| 3 | xxxxxxxxxxx |
| 4 | yyyyyyyyyyy |
client
| id | firstname | lastname |
+----+-----------+------------+
| 3 | Sofia | Lenhark |
| 4 | Mark | Davoreski |
Now I need to select the following fields in a SQL Query:
Source Firstname
Source Lastname
Destination Firstname
Destination Lastname
Payment Value
I have tried the following:
SELECT
srcClientDetails.firstname,
srcClientDetails.lastname,
destClientDetails.firstname,
destClientDetails.lastname,
Payments.payment_value
FROM
dbo.payment AS Payments
LEFT JOIN dbo.client_account AS srcClientAccount ON Payments.src_account = srcClientAccount.account_id
LEFT JOIN dbo.client AS srcClientDetails ON srcClientAccount.client_id = srcClientDetails.id
LEFT JOIN dbo.client_account AS destClientAccount ON Payments.dest_account = destClientAccount.account_id
LEFT JOIN dbo.client AS destClientDetails ON destClientAccount.client_id = destClientDetails.id
But this is returning only the payment value, without any other data.
Why aren't the other desired fields being returned?

Answer 1

Suggestions
(1) Try it in INNER JOIN
To check that the JOIN is correct (Values are equal),first test the query using INNER JOIN
SELECT *
FROM dbo.payment AS Payments
INNER JOIN dbo.client_account AS srcClientAccount ON Payments.src_account =
srcClientAccount.account_id
and check if it returns values or not, then add another table:
SELECT *
FROM dbo.payment AS Payments
INNER JOIN dbo.client_account AS srcClientAccount ON Payments.src_account =
srcClientAccount.account_id
INNER JOIN dbo.client AS srcClientDetails ON srcClientAccount.client_id = srcClientDetails.id
And so on... This may leads you to the issue
(2) Account id difference due to collation or additional spaces
I think this will lead you to the problem, it may be caused due to a case sensitive collation or length sensitive or additional spaces. To diagnose this issue, you can also try converting both columns to same case and length and Trim additional spaces.
ON LTRIM(RTRIM(UPPER(CAST(Payments.src_account as varchar(50))))) = LTRIM(RTRIM(UPPER(CAST(srcClientAccount.account_id as varchar(50)))))
If this fixes the problem than it is better to edit the data (adding relations or constraints) rather than using this functions in the Join because it decrease the performance and doesn't use indexes.
(3) Create relations between tables
From the question it seems that there is no relation between columns, create the relations so values are constrained.

Answer 2

Your logic was right, just the [client_account].account_id was 1 'y' short for matching, or Payments.dest_account needs 1 less 'y'.
For example, you can see here I added 1 'y' to the [client_account].account_id and your query now returns the correct information:
WITH Payments AS (
SELECT '1' as id,
'xxxxxxxxxxx' as src_account,
'yyyyyyyyyyyy' as dest_account,
'200' as payment_value),
client_account AS (
SELECT '3' as client_id,
'xxxxxxxxxxx' as account_id
UNION ALL
SELECT '4' as client_id,
'yyyyyyyyyyyy' as 'account_id'), --added a 'y' here
client AS (
SELECT '3' as id,
'Sofia' as firstname,
'Lenhark' as lastname
UNION ALL
SELECT '4' as id,
'Mark' as firstname,
'Davoreski' as lastname)
SELECT
srcClientDetails.firstname,
srcClientDetails.lastname,
destClientDetails.firstname,
destClientDetails.lastname,
Payments.payment_value
FROM
payments AS Payments
LEFT JOIN client_account AS srcClientAccount ON Payments.src_account = srcClientAccount.account_id
LEFT JOIN client AS srcClientDetails ON srcClientAccount.client_id = srcClientDetails.id
LEFT JOIN client_account AS destClientAccount ON Payments.dest_account = destClientAccount.account_id
LEFT JOIN client AS destClientDetails ON destClientAccount.client_id = destClientDetails.id
Try it here