postgresql function with multiple columns output - sql

Question

SELECT column_name as name,
data_type,
concat(character_maximum_length,numeric_precision,datetime_precision) as length,
concat(numeric_precision,datetime_precision) as prec,
is_nullable as isnullable,
COALESCE(numeric_scale,'0') as scale,
null as definition,
null as iscomputed,
null as is_sparse,
column_default as "default",
null as is_persisted
FROM information_schema.columns
WHERE (table_schema, table_name) = ('test', 'testtable')
ORDER BY ordinal_position;
Current output:
name | data_type | length | prec | isnullable | scale | definition | iscomputed | is_sparse | default | is_persisted
----------------------+-----------------------------+--------+------+------------+-------+------------+------------+-----------+--------------------+--------------
keytestpostgresql | uuid | | | NO | 0 | | | | uuid_generate_v4() |
testsmalldatetime | timestamp without time zone | 0 | 0 | YES | 0 | | | | |
testdatetime | timestamp without time zone | 3 | 3 | YES | 0 | | | | |
testint | integer | 32 | 32 | YES | 0 | | | | |
testdatenotime | date | 0 | 0 | YES | 0 | | | | |
testnmemo | text | | | YES | 0 | | | | |
testfloat | double precision | 53 | 53 | YES | 0 | | | | |
testboolean | boolean | | | YES | 0 | | | | |
biginttest | bigint | 64 | 64 | YES | 0 | | | | |
testtinyint | smallint | 16 | 16 | YES | 0 | | | | |
testsmallint | smallint | 16 | 16 | YES | 0 | | | | |
testuniqueidentifier | uuid | | | YES | 0 | | | | |
testnumeric | numeric | 5 | 5 | YES | 2 | | | | |
updoperation | smallint | 16 | 16 | NO | 0 | | | | 0 |
upddate | timestamp without time zone | 3 | 3 | NO | 0 | | | | now() |
(15 rows)
Want column length to return or show value in output as -1 if blank or null
Want column prec to return or show value in output as 0 if blank or null

Answer 1

Please refer below Query:
SELECT column_name as name,
data_type,
coalesce(character_maximum_length, numeric_precision, datetime_precision, -1) as length,
concat(numeric_precision,datetime_precision) as prec,
is_nullable as isnullable,
COALESCE(numeric_scale,'0') as scale,
null as definition,
null as iscomputed,
null as is_sparse,
column_default as "default",
null as is_persisted
FROM information_schema.columns
WHERE (table_schema, table_name) = ('test', 'testtable')
ORDER BY ordinal_position;