I have a table in PostgreSQL which has field like id,name,city,mob
etc. i got that in PostgreSQL there is json data type in which we can
store the data in json format but I don't want to use json data type.
I want to fetch these table field (id,name,city,mob) which are normal fields not json data type field that I want in json format
I want that suppose mytable is a table which has id,name,city,mob,dob as field and
now i want to execute query like:
select name,city from mytable where id=5;
select row_to_json(t) from ( select name,city from mytable where id=5 ) t
The derived table is necessary to create a record type with proper names for the columns.
row_to_json((name,city)) would not achieve this.
If you want all columns from the table (not just two as shown in the question) then you don't need the derived table:
select row_to_json(mytable) from mytable where id = 5;