匹配值列sql

Question

Helllo, Im tying to match value of col1 in tab1. IF value == 'Tri/' then tab1.col2 == 's1'. IF value == 'Tri/v1/v11/' then 's2'. I wrote the code below but not works in my case (if col1 == 'Tri/v1/v11/' then s1 which not what im seeking.

case
when vh_state like '%Tri/%' then 's1'
when vh_state like'%Tri/v1/v11/%' then 's2'
else 'UNkown choice'
end as col2

Answer 1

These are evaluated in order, so you need to put the most restrictive first:

(case when vh_state like '%Tri/v1/v11/%' then 's2'
      when vh_state like '%Tri/%' then 's1'
      else 'Inconnu'
 end) as col2

If you don't readily know which is the most restrictive, you could use a subquery to match the longest:

(select v.value
 from (values ('%Tri/v1/v11/%', 's2'),
              ('%Tri/%', 's1'),
      ) v(pattern, value)
 where vh_state like v.pattern
 order by length(pattern) desc  
 limit 1
)               

Answer 2

The issue is you have used '%Tri/%' in the first case statement, which qualifies the value Tri/v1/v11/ since it is a like operator resulting in S1 for both the cases. Change the order of case statement to make it work properly

Use below query,

case when vh_state like '%Tri/v1/v11/%' then 's2'
  when vh_state like '%Tri/%' then 's1'
  else 'Inconnu'
 end as col2