String match in Postgresql - postgresql

Question

I am trying to make separate columns in my query result for values stored in in a single column. It is a string field that contains a variety of similar values stored like this:
["john"] or ["john", "jane"] or ["john", "john smith', "jane"],etc... where each of the values in quotes is a distinct value. I cannot seem to isolate just ["john"] in a way that will return john and not john smith. The john smith value would be in a separate column. Essentially a column for each value in quotes. Note, I would like the results to not contain the quotes or the brackets.
I started with:
Select name
From namestbl
Where name like %["john"]%;
I think this is heading in the wrong direction. I think this should be in select instead of where.
Sorry about the format, I give up trying to figure out the completely useless error message when i try to save this with table markdown.

Answer 1

Your data examples represent valid JSON array syntax. So cast them to JSONB array and access individual elements by position (JSON arrays are zero based). The t CTE is a mimic of real data. In the illustration below the number of columns is limited to 6.
with t(s) as
(
values
('["john", "john smith", "jane"]'),
('["john", "jane"]'),
('["john"]')
)
select s::jsonb->>0 name1, s::jsonb->>1 name2, s::jsonb->>2 name3,
s::jsonb->>3 name4, s::jsonb->>4 name5, s::jsonb->>5 name6
from t;
Here is the result.
name1
name2
name3
name4
name5
name6
john
john smith
jane
john
jane
john