How to select one instance each, based on distinct column values using UNION

This is the input data:
enter image description here

I just want 1 instance for each work_contract.

I tried to use LIMIT 1 and used UNION ALL as well as UNION DISTINCT but it appears we can’t use LIMIT in UNION.

SELECT *,
FROM table1 
where work_contract = "SECONDMENT" 
LIMIT 1

UNION DISTINCT

SELECT *,
FROM table1 
where work_contract = "INTER" 
LIMIT 1

UNION DISTINCT

SELECT *,
FROM table1 
where work_contract = "CASUAL" 
LIMIT 1

This doesn’t work. Is there a way to choose only 1 instance at work_contract level?

>Solution :

you can use below query. I am assuming here you don’t want to include at employee id level and its just work_contract level.

SELECT *,
FROM table 1 
where work_contract = "SECONDMENT" 
qualify ( row_number() over  (partition by work_contract order by employee_id,employee_type_description) = 1)

UNION DISTINCT

SELECT *,
FROM table 1   
where work_contract = "INTER" 
qualify ( row_number() over  (partition by work_contract order by employee_id,employee_type_description) = 1)

UNION DISTINCT

SELECT *,
FROM table 1   
where work_contract = "CASUAL" 
qualify ( row_number() over  (partition by work_contract order by employee_id,employee_type_description) = 1)