Match column name with data from other table

I have dynamically created a temp table #temp1 that create column dynamically based on a json string. The table will look like as below

#temp1

ID	Field	FRUIT	VEGE
1	Field1	A	B
2	Field2	C	D

I would like to fill in the value column only in result table based on the #temp1 table, the field and type_id is already filled beforehand

result table

ID	field	type_id	value
1	Field1	1	A
2	Field1	2	B
3	Field2	1	C
4	Field2	2	D

where the type_id can get from another table that specified the type and its id

type table

ID	type_id	type
1	1	FRUIT
2	2	VEGE

The type table will have many different types in it, I just list out the only two that is used in this question only.

Please help!

my attempt query:

update B
        set B.value = ' value B.column_name in #result match with'
        from result_table B
        inner join type_table D
        on D.type = 'column name in result_table'

Answer

You will need to use Dynamic Query as your column is dynamic

declare @sql       nvarchar(max),
        @case_stmt nvarchar(max)

-- form the case statement
select @case_stmt = STRING_AGG ('WHEN ''' + type + ''' THEN t1.' + quotename(t.type), char(13))
from   typ t
where  exists 
       (
           select *
           from   result r 
           where  t.type_id = r.type_id
       )

-- Print out for insepction
print @case_stmt

-- form final query
select @sql = 'update r' + char(13)
            + 'set value = CASE t.type' + char(13)
            + @case_stmt + char(13)
            + 'END'+ char(13)
            + 'from   result r' + char(13)
            + 'inner join #temp1 t1 on r.Field = t1.Field' + char(13)
            + 'inner join typ t     on r.type_id = t.type_id' + char(13)
-- Print out for insepction
print @sql            

exec (@sql);

select *
from  result

note : char(13) is new line. It helps to do simple formatting of the query

db<>fiddle demo