Remove Duplicate rows in left join base on one column - mysql

Question

I want to remove the duplicates column with the same id. I want to keep only the first one that shows up.
SELECT t.ticketId ,t.userIdOwner , t.ticketCreateDatetime , t.ticketExpectedEndDatetime , t.ticketUpdateDatetime, t.ticketUpdateBy, t.ticketLabel,t.statusTypeIdTicketState,t.statusTypeIdTicketType,t.statusTypeIdTicketModule,
c.clientLabel, c.clientLogoOnList ,s.taskLabel , s.statusTypeIdTaskCompletion
FROM ticket AS t
INNER JOIN client AS c
ON c.clientId = t.clientId
LEFT JOIN task AS s
ON s.ticketId = t.ticketId AND s.statusTypeIdTaskCompletion = (SELECT statusTypeId FROM statusType WHERE statusTypeCode = 'waitingTask' AND statusTypeTargetTable = 'statusTypeIdTaskCompletion' )
WHERE 1=1
AND t.ticketDeleteDatetime IS NULL
Here's my screen of results
Edit Image query all results
enter image description here
Edit Image of task structure table :
enter image description here

Answer 1

You probably have more tasks for each ticket with same statusType
so, if you don't care about different tasks, you can simply add a DISTINCT clause in your SELECT
SELECT DISTINCT
t.ticketId ,t.userIdOwner , t.ticketCreateDatetime , t.ticketExpectedEndDatetime ,
t.ticketUpdateDatetime, t.ticketUpdateBy, t.ticketLabel,t.statusTypeIdTicketState,
t.statusTypeIdTicketType,t.statusTypeIdTicketModule,
c.clientLabel, c.clientLogoOnList ,s.taskLabel , s.statusTypeIdTaskCompletion
FROM ticket AS t
INNER JOIN client AS c ON c.clientId = t.clientId
LEFT JOIN task AS s ON s.ticketId = t.ticketId AND s.statusTypeIdTaskCompletion = (
SELECT statusTypeId
FROM statusType
WHERE statusTypeCode = 'waitingTask'
AND statusTypeTargetTable = 'statusTypeIdTaskCompletion'
)
WHERE 1=1
AND t.ticketDeleteDatetime IS NULL
ok, after your edit, now we can see, that the problem is that more than one task is eligible for the ticket.
Unfortunaterly "the first that show up" is not a valid SQL statement (because the same query could give different results depending on different circumnstances).
So you have to decide wich one to keep, you need to decide a rule, a logic to keep one of the rows.
If you don't need the task label you can simply strip off that column and use the DISTINCT.
If you want to show a task label but don't mind which one, you can use MAX(s.taskLabel) and group by on all other columns.
If you want to keep the last task for that ticket you should provide informations about cronological order (a datetime column or an autoincrement column)
Example with MAX(taskLabel):
SELECT
t.ticketId,
t.userIdOwner,
t.ticketCreateDatetime,
t.ticketExpectedEndDatetime,
t.ticketUpdateDatetime,
t.ticketUpdateBy,
t.ticketLabel,
t.statusTypeIdTicketState,
t.statusTypeIdTicketType,
t.statusTypeIdTicketModule,
c.clientLabel,
c.clientLogoOnList,
s.taskLabel,
s.statusTypeIdTaskCompletion
FROM ticket AS t
INNER JOIN client AS c ON c.clientId = t.clientId
LEFT JOIN (
SELECT s.ticketId, MAX(s.taskLabel) AS taskLabel
FROM task AS s
WHERE s.statusTypeIdTaskCompletion = (
SELECT statusTypeId
FROM statusType
WHERE statusTypeCode = 'waitingTask'
AND statusTypeTargetTable = 'statusTypeIdTaskCompletion'
)
GROUP BY s.ticketId
) S ON s.ticketId = t.ticketId
WHERE 1=1
AND t.ticketDeleteDatetime IS NULL