should be it

external/duckdb/test/sql/pg_catalog/pg_attribute.test

@@ -0,0 +1,17 @@
+# name: test/sql/pg_catalog/pg_attribute.test
+# description: Test pg_attribute function
+# group: [pg_catalog]
+
+query IIIIII nosort pg_attribute
+SELECT * FROM pg_attribute
+
+query IIIIII nosort pg_attribute
+SELECT * FROM pg_catalog.pg_attribute
+
+statement ok
+CREATE TABLE integers(i integer)
+
+query III
+select relname, attname, attnum from pg_attribute join pg_class on (pg_attribute.attrelid=pg_class.oid) where relname='integers' and attnum>=0;
+----
+integers	i	1

external/duckdb/test/sql/pg_catalog/pg_constraint.test

@@ -0,0 +1,25 @@
+# name: test/sql/pg_catalog/pg_constraint.test
+# description: Test pg_constraint function
+# group: [pg_catalog]
+
+query IIIIII nosort pg_constraint
+SELECT * FROM pg_constraint
+
+statement ok
+create table a (id int , primary key (id));
+
+statement ok
+create table b (id int , foreign_a int, foreign key (foreign_a) references a);
+
+statement ok
+insert into a (id) values (0);
+
+statement ok
+insert into b (id, foreign_a) VALUES (0, 0);
+
+query IIIIIIIIIIIIIIIIIIIIII
+SELECT * EXCLUDE (OID, CONRELID, connamespace) FROM pg_catalog.pg_constraint
+----
+PRIMARY KEY(id)								p	false	false	true	0	0	0	0	NULL	NULL	NULL	true	0	false	[0]	NULL	NULL	NULL	NULL	NULL	NULL
+NOT NULL									x	false	false	true	0	0	0	0	NULL	NULL	NULL	true	0	false	[0]	NULL	NULL	NULL	NULL	NULL	NULL
+FOREIGN KEY (foreign_a) REFERENCES a(id)	f	false	false	true	0	0	0	0	NULL	NULL	NULL	true	0	false	[1]	NULL	NULL	NULL	NULL	NULL	NULL

external/duckdb/test/sql/pg_catalog/pg_database.test

@@ -0,0 +1,9 @@
+# name: test/sql/pg_catalog/pg_database.test
+# description: Test pg_database function
+# group: [pg_catalog]
+
+query II nosort pg_dbase
+SELECT * FROM pg_database
+
+query II nosort pg_dbase
+SELECT * FROM pg_catalog.pg_database

external/duckdb/test/sql/pg_catalog/pg_depend.test

@@ -0,0 +1,9 @@
+# name: test/sql/pg_catalog/pg_depend.test
+# description: Test pg_depend function
+# group: [pg_catalog]
+
+query IIIIII nosort pg_depend
+SELECT * FROM pg_depend ORDER BY ALL
+
+query IIIIII nosort pg_depend
+SELECT * FROM pg_catalog.pg_depend ORDER BY ALL

external/duckdb/test/sql/pg_catalog/pg_enum.test

@@ -0,0 +1,9 @@
+# name: test/sql/pg_catalog/pg_enum.test
+# description: Test pg_enum function
+# group: [pg_catalog]
+
+query IIIIII nosort pg_enum
+SELECT * FROM pg_enum
+
+query IIIIII nosort pg_enum
+SELECT * FROM pg_catalog.pg_enum

external/duckdb/test/sql/pg_catalog/pg_index.test

@@ -0,0 +1,21 @@
+# name: test/sql/pg_catalog/pg_index.test
+# description: Test pg_index function
+# group: [pg_catalog]
+
+statement ok
+CREATE TABLE integers(i INTEGER, j INTEGER, k INTEGER)
+
+statement ok
+CREATE INDEX i_index ON integers((j + 1), k)
+
+query IIIIII nosort pg_index
+SELECT * FROM pg_index
+
+query IIIIII nosort pg_index
+SELECT * FROM pg_catalog.pg_index
+
+query IIIIII nosort pg_indexes
+SELECT * FROM pg_indexes
+
+query IIIIII nosort pg_indexes
+SELECT * FROM pg_catalog.pg_indexes

external/duckdb/test/sql/pg_catalog/pg_namespace.test

@@ -0,0 +1,41 @@
+# name: test/sql/pg_catalog/pg_namespace.test
+# description: Test pg_namespace function
+# group: [pg_catalog]
+
+require skip_reload
+
+query I
+SELECT COUNT(*) FROM pg_namespace WHERE nspname='myschema'
+----
+0
+
+statement ok
+CREATE SCHEMA myschema
+
+query I
+SELECT COUNT(*) FROM pg_namespace WHERE nspname='myschema'
+----
+1
+
+# can query through the "pg_catalog" namespace
+query IIII nosort pgnamespace
+SELECT * FROM pg_namespace
+
+query IIII nosort pgnamespace
+SELECT * FROM pg_catalog.pg_namespace
+
+# oid of an entry does not change even after adding new entries
+query I nosort pgmyschema
+SELECT * FROM pg_namespace WHERE nspname='myschema'
+
+statement ok
+CREATE SCHEMA bla
+
+statement ok
+CREATE SCHEMA test
+
+statement ok
+CREATE SCHEMA myschema33
+
+query I nosort pgmyschema
+SELECT * FROM pg_namespace WHERE nspname='myschema'

external/duckdb/test/sql/pg_catalog/pg_prepared_statements.test

@@ -0,0 +1,25 @@
+# name: test/sql/pg_catalog/pg_prepared_statements.test
+# group: [pg_catalog]
+
+statement ok
+prepare p1 as select 42;
+
+statement ok
+create table tbl(a varchar);
+
+statement ok
+prepare p2 as insert into tbl values ('test');
+
+statement ok
+prepare p3 as select 21, $1, $2
+
+statement ok
+prepare p4 as select $name, $other_name
+
+query IIIIIIII
+select * from pg_prepared_statements order by name;
+----
+p1	SELECT 42	NULL	NULL	[INTEGER]	NULL	NULL	NULL
+p2	INSERT INTO tbl (VALUES ('test'))	NULL	NULL	[BIGINT]	NULL	NULL	NULL
+p3	SELECT 21, $1, $2	NULL	[UNKNOWN, UNKNOWN]	NULL	NULL	NULL	NULL
+p4	SELECT $name, $other_name	NULL	[UNKNOWN, UNKNOWN]	NULL	NULL	NULL	NULL

external/duckdb/test/sql/pg_catalog/pg_privilege.test

@@ -0,0 +1,22 @@
+# name: test/sql/pg_catalog/pg_privilege.test
+# description: Test Postgres compatibility privilege functions
+# group: [pg_catalog]
+
+foreach function has_any_column_privilege has_database_privilege has_foreign_data_wrapper_privilege has_function_privilege has_language_privilege has_schema_privilege has_sequence_privilege has_server_privilege has_table_privilege has_tablespace_privilege
+
+query I
+SELECT ${function}('main', 'test')
+----
+true
+
+query I
+SELECT ${function}(current_user, 'main', 'test')
+----
+true
+
+endloop
+
+query II
+SELECT has_column_privilege('main', 'test', 'col'), has_column_privilege(current_user, 'main', 'test', 'col')
+----
+true	true

external/duckdb/test/sql/pg_catalog/pg_proc.test_slow

@@ -0,0 +1,43 @@
+# name: test/sql/pg_catalog/pg_proc.test_slow
+# description: Test pg_proc function
+# group: [pg_catalog]
+
+statement ok
+PRAGMA enable_verification
+
+statement ok
+SELECT * FROM pg_proc;
+
+statement ok
+CREATE MACRO add_default1(a := 3, b := 5) AS a + b
+
+statement ok
+CREATE MACRO add_default2(a, b := 5) AS a + b
+
+statement ok
+SELECT * FROM pg_proc;
+
+query I
+select distinct proname from pg_proc where proname='sqrt';
+----
+sqrt
+
+query IIIIII
+select proisagg, prorettype, proargtypes, proargnames, pronargs, provolatile FROM pg_proc WHERE proname='corr';
+----
+true	DOUBLE	[DOUBLE, DOUBLE]	[y, x]	2	i
+
+query IIII
+select provariadic, prorettype, proargtypes, proargnames FROM pg_proc WHERE proname='printf';
+----
+ANY	VARCHAR	[VARCHAR]	[format]
+
+query II
+SELECT prokind, provolatile FROM pg_proc WHERE proname = 'random' 
+----
+f	v
+
+query I
+SELECT length(prosqlbody) > 0 FROM pg_proc WHERE proname = 'add_default1'
+----
+true

external/duckdb/test/sql/pg_catalog/pg_sequence.test

@@ -0,0 +1,17 @@
+# name: test/sql/pg_catalog/pg_sequence.test
+# description: Test pg_sequence function
+# group: [pg_catalog]
+
+statement ok
+CREATE SEQUENCE seq
+
+query IIIIII nosort pg_seq
+SELECT * FROM pg_sequence
+
+query IIIIII nosort pg_seq
+SELECT * FROM pg_catalog.pg_sequence
+
+query IIIII
+SELECT seqstart, seqincrement, seqmax, seqmin, seqcycle FROM pg_sequence
+----
+1	1	9223372036854775807	1	False

external/duckdb/test/sql/pg_catalog/pg_sequences.test

@@ -0,0 +1,17 @@
+# name: test/sql/pg_catalog/pg_sequences.test
+# description: Test pg_sequences function
+# group: [pg_catalog]
+
+statement ok
+CREATE SEQUENCE seq
+
+query IIIIII nosort pg_seq
+SELECT * FROM pg_sequences
+
+query IIIIII nosort pg_seq
+SELECT * FROM pg_catalog.pg_sequences
+
+query IIIII
+SELECT sequencename, min_value, max_value, start_value, cycle FROM pg_sequences
+----
+seq	1	9223372036854775807	1	False

external/duckdb/test/sql/pg_catalog/pg_settings.test

@@ -0,0 +1,22 @@
+# name: test/sql/pg_catalog/pg_settings.test
+# description: Test pg_settings function
+# group: [pg_catalog]
+
+statement ok
+SET default_null_order='nulls_first';
+
+statement ok
+SELECT * FROM pg_settings;
+
+query II
+SELECT name, setting FROM pg_settings WHERE name='default_null_order';
+----
+default_null_order	NULLS_FIRST
+
+statement ok
+SET default_null_order='nulls_last'
+
+query II
+SELECT name, setting FROM pg_settings WHERE name='default_null_order';
+----
+default_null_order	NULLS_LAST

external/duckdb/test/sql/pg_catalog/pg_tablespace.test

@@ -0,0 +1,9 @@
+# name: test/sql/pg_catalog/pg_tablespace.test
+# description: Test pg_tablespace function
+# group: [pg_catalog]
+
+query IIIIII nosort pg_tspace
+SELECT * FROM pg_tablespace
+
+query IIIIII nosort pg_tspace
+SELECT * FROM pg_catalog.pg_tablespace

external/duckdb/test/sql/pg_catalog/pg_type.test

@@ -0,0 +1,117 @@
+# name: test/sql/pg_catalog/pg_type.test
+# description: Test pg_type function
+# group: [pg_catalog]
+
+statement ok
+CREATE TYPE greeting AS ENUM('hi', 'bonjour', 'konnichiwa', 'howdy')
+
+statement ok
+SELECT * FROM pg_type
+
+statement ok
+SELECT * FROM pg_catalog.pg_type
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'int8' AND oid IS NOT NULL
+----
+20
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'bytea' AND oid IS NOT NULL
+----
+17
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'bit' AND oid IS NOT NULL
+----
+1560
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'bool' AND oid IS NOT NULL
+----
+16
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'varchar' AND oid IS NOT NULL
+----
+1043
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'date' AND oid IS NOT NULL
+----
+1082
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'float8' AND oid IS NOT NULL
+----
+701
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'float4' AND oid IS NOT NULL
+----
+700
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'uuid' AND oid IS NOT NULL
+----
+2950
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'int4' AND oid IS NOT NULL
+----
+23
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'int2' AND oid IS NOT NULL
+----
+21
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'interval' AND oid IS NOT NULL
+----
+1186
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'time' AND oid IS NOT NULL
+----
+1083
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'timestamp' AND oid IS NOT NULL
+----
+1114
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'timestamptz' AND oid IS NOT NULL
+----
+1184
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'timetz' AND oid IS NOT NULL
+----
+1266
+
+query I
+SELECT count(*) FROM pg_type where typname = 'greeting'
+----
+1
+
+query I
+SELECT oid FROM pg_type WHERE typname = 'numeric' AND oid IS NOT NULL
+----
+1700
+
+query I
+SELECT count(*) FROM pg_type where typname = 'enum' AND oid is NOT NULL
+----
+0
+
+query I
+SELECT pg_catalog.format_pg_type('DECIMAL', 'test');
+----
+numeric
+
+query I
+SELECT pg_catalog.format_pg_type('decimal', 'test');
+----
+numeric

external/duckdb/test/sql/pg_catalog/pg_views.test

@@ -0,0 +1,17 @@
+# name: test/sql/pg_catalog/pg_views.test
+# description: Test pg_views function
+# group: [pg_catalog]
+
+statement ok
+CREATE VIEW v1 AS SELECT 42
+
+query IIIIII nosort pg_view
+SELECT * FROM pg_views
+
+query IIIIII nosort pg_view
+SELECT * FROM pg_catalog.pg_views
+
+query II
+SELECT viewname, viewowner FROM pg_views WHERE viewname='v1'
+----
+v1	duckdb

external/duckdb/test/sql/pg_catalog/sqlalchemy.test

@@ -0,0 +1,378 @@
+# name: test/sql/pg_catalog/sqlalchemy.test
+# description: Test postgres catalog queries from SQL Alchemy to test postgres compatibility on this frnot
+# group: [pg_catalog]
+
+# https://github.com/sqlalchemy/sqlalchemy/blob/master/lib/sqlalchemy/dialects/postgresql/base.py
+
+statement ok
+CREATE TYPE greeting AS ENUM('hi', 'bonjour', 'konnichiwa', 'howdy')
+
+statement ok
+CREATE TABLE integral_values (
+    j smallint,
+    k integer,
+    l bigint,
+    i real,
+    z double precision,
+    m DECIMAL(4, 1),
+    n DECIMAL(9, 2),
+    o DECIMAL(18, 4),
+    p DECIMAL(37, 2),
+    q varchar,
+    r bytea,
+    s date,
+    t time,
+    u timestamp,
+	v date[],
+	w greeting
+);
+
+# has_schema
+query I
+select distinct nspname from pg_namespace " "where lower(nspname)='main'
+----
+main
+
+# has_table
+query I
+select relname from pg_class c join pg_namespace n on
+n.oid=c.relnamespace where
+pg_catalog.pg_table_is_visible(c.oid)
+and relname='integral_values'
+----
+integral_values
+
+query I
+select relname from pg_class c join pg_namespace n on
+n.oid=c.relnamespace where
+pg_catalog.pg_table_is_visible(c.oid)
+and relname='f'
+----
+
+
+# has_table with an explicit schema
+query I
+select relname from pg_class c join pg_namespace n on
+n.oid=c.relnamespace where n.nspname='main' and
+relname='integral_values'
+----
+integral_values
+
+query I
+select relname from pg_class c join pg_namespace n on
+n.oid=c.relnamespace where n.nspname='main' and
+relname='f'
+----
+
+# has_sequence
+statement ok
+CREATE SEQUENCE seq
+
+query I
+SELECT relname FROM pg_class c join pg_namespace n on
+n.oid=c.relnamespace where relkind='S' and
+n.nspname='main' and relname='seq'
+----
+seq
+
+query I
+SELECT relname FROM pg_class c join pg_namespace n on
+n.oid=c.relnamespace where relkind='S' and
+n.nspname='main' and relname='f'
+----
+
+# has_type
+query I
+SELECT EXISTS (
+	SELECT * FROM pg_catalog.pg_type t, pg_catalog.pg_namespace n
+	WHERE t.typnamespace = n.oid
+	AND t.typname = 'integer'
+	AND n.nspname = 'main'
+	)
+----
+false
+
+query I
+SELECT EXISTS (
+	SELECT * FROM pg_catalog.pg_type t, pg_catalog.pg_namespace n
+	WHERE t.typnamespace = n.oid
+	AND t.typname = 'int4'
+	AND n.nspname = 'main'
+	)
+----
+true
+
+# get_table_oid
+query I
+SELECT COUNT(c.oid)
+FROM pg_catalog.pg_class c
+LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
+WHERE (pg_catalog.pg_table_is_visible(c.oid))
+AND c.relname = 'integral_values' AND c.relkind in
+('r', 'v', 'm', 'f', 'p')
+----
+1
+
+# get_schema_names
+statement ok
+SELECT nspname FROM pg_namespace
+WHERE nspname NOT LIKE 'pg_%'
+ORDER BY nspname
+
+# get_table_names
+query I
+SELECT c.relname FROM pg_class c
+JOIN pg_namespace n ON n.oid = c.relnamespace
+WHERE n.nspname = 'main' AND c.relkind in ('r', 'p')
+----
+integral_values
+
+# _get_foreign_table_names
+statement ok
+SELECT c.relname FROM pg_class c
+JOIN pg_namespace n ON n.oid = c.relnamespace
+WHERE n.nspname = 'main' AND c.relkind = 'f'
+
+# get_view_names
+statement ok
+CREATE SCHEMA myschema
+
+statement ok
+CREATE VIEW myschema.v1 AS SELECT 42;
+
+query I
+SELECT c.relname FROM pg_class c
+JOIN pg_namespace n ON n.oid = c.relnamespace
+WHERE n.nspname = 'myschema' AND c.relkind IN ('v', 'm')
+----
+v1
+
+# get_sequence_names
+query I
+SELECT relname FROM pg_class c join pg_namespace n on
+n.oid=c.relnamespace where relkind='S' and
+n.nspname='main'
+----
+seq
+
+# get_view_definition
+query I
+SELECT string_split_regex(pg_get_viewdef(c.oid), '\n')[1] view_def FROM pg_class c
+JOIN pg_namespace n ON n.oid = c.relnamespace
+WHERE n.nspname = 'myschema' AND c.relname = 'v1'
+AND c.relkind IN ('v', 'm')
+----
+CREATE VIEW myschema.v1 AS SELECT 42;
+
+# get_columns
+query IIII
+SELECT a.attname,
+	pg_catalog.format_type(a.atttypid, a.atttypmod),
+	(
+	SELECT pg_catalog.pg_get_expr(d.adbin, d.adrelid)
+	FROM pg_catalog.pg_attrdef d
+	WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum
+	AND a.atthasdef
+	) AS DEFAULT,
+	a.attnotnull
+FROM pg_catalog.pg_attribute a
+LEFT JOIN pg_catalog.pg_description pgd ON (
+	pgd.objoid = a.attrelid AND pgd.objsubid = a.attnum)
+WHERE a.attrelid = (SELECT MIN(oid) FROM pg_class WHERE relname='integral_values')
+AND a.attnum > 0 AND NOT a.attisdropped
+ORDER BY a.attnum;
+----
+j	int2	NULL	false
+k	int4	NULL	false
+l	int8	NULL	false
+i	float4	NULL	false
+z	float8	NULL	false
+m	numeric(4,1)	NULL	false
+n	numeric(9,2)	NULL	false
+o	numeric(18,4)	NULL	false
+p	numeric(37,2)	NULL	false
+q	varchar	NULL	false
+r	bytea	NULL	false
+s	date	NULL	false
+t	time	NULL	false
+u	timestamp	NULL	false
+v	list	NULL	false
+w	enum	NULL	false
+
+
+# get_pk_constraint
+statement ok
+SELECT a.attname
+FROM
+	pg_class t
+	join pg_index ix on t.oid = ix.indrelid
+	join pg_attribute a
+		on t.oid=a.attrelid
+	WHERE
+	t.oid = (SELECT MIN(table_oid) FROM duckdb_tables) and ix.indisprimary = 't'
+ORDER BY a.attnum
+
+
+# get_pk_constraint, >= v8.4
+statement ok
+SELECT a.attname
+FROM pg_attribute a JOIN (
+	SELECT unnest(ix.indkey) attnum,
+			generate_subscripts(ix.indkey, 1) ord
+	FROM pg_index ix
+	WHERE ix.indrelid = (SELECT MIN(table_oid) FROM duckdb_tables) AND ix.indisprimary
+	) k ON a.attnum=k.attnum
+WHERE a.attrelid = (SELECT MIN(table_oid) FROM duckdb_tables)
+ORDER BY k.ord
+
+# get_foreign_keys
+statement ok
+SELECT r.conname,
+	pg_catalog.pg_get_constraintdef(r.oid, true) as condef,
+	n.nspname as conschema
+FROM  pg_catalog.pg_constraint r,
+	pg_namespace n,
+	pg_class c
+WHERE r.conrelid = (SELECT MIN(table_oid) FROM duckdb_tables) AND
+	r.contype = 'f' AND
+	c.oid = confrelid AND
+	n.oid = c.relnamespace
+ORDER BY 1
+
+# get_unique_constraints
+statement ok
+SELECT
+	cons.conname as name,
+	cons.conkey as key,
+	a.attnum as col_num,
+	a.attname as col_name
+FROM
+	pg_catalog.pg_constraint cons
+	join pg_attribute a
+		on cons.conrelid = a.attrelid AND
+		a.attnum = ANY(cons.conkey)
+WHERE
+	cons.conrelid = (SELECT MIN(table_oid) FROM duckdb_tables) AND
+	cons.contype = 'u'
+
+# get_indexes
+statement ok
+SELECT
+	i.relname as relname,
+	ix.indisunique, ix.indexprs, ix.indpred,
+	a.attname, a.attnum, NULL, ix.indkey,
+	am.amname,
+	NULL as indnkeyatts
+FROM
+	pg_class t
+		join pg_index ix on t.oid = ix.indrelid
+		join pg_class i on i.oid = ix.indexrelid
+		left outer join
+			pg_attribute a
+			on t.oid = a.attrelid
+		left outer join
+			pg_am am
+			on i.relam = am.oid
+WHERE
+	t.relkind IN ('r', 'v', 'f', 'm')
+	and t.oid = (SELECT MIN(table_oid) FROM duckdb_tables)
+	and ix.indisprimary = 'f'
+ORDER BY
+	t.relname,
+	i.relname
+
+mode skip
+# FIXME: ANY(list) in left outer join
+# this will be fixed by either allowing subqueries in left-outer joins
+# or by modifying ANY(list) to be a function instead of a rewrite to a subquery
+
+statement ok
+SELECT
+	i.relname as relname,
+	ix.indisunique, ix.indexprs,
+	a.attname, a.attnum, c.conrelid, ix.indkey::varchar,
+	ix.indoption::varchar, i.reloptions, am.amname,
+	pg_get_expr(ix.indpred, ix.indrelid)
+FROM
+	pg_class t
+		join pg_index ix on t.oid = ix.indrelid
+		join pg_class i on i.oid = ix.indexrelid
+		left outer join
+			pg_attribute a
+			on t.oid = a.attrelid and a.attnum = ANY(ix.indkey)
+		left outer join
+			pg_constraint c
+			on (ix.indrelid = c.conrelid and
+				ix.indexrelid = c.conindid and
+				c.contype in ('p', 'u', 'x'))
+		left outer join
+			pg_am am
+			on i.relam = am.oid
+WHERE
+	t.relkind IN ('r', 'v', 'f', 'm', 'p')
+	and t.oid = (SELECT MIN(table_oid) FROM duckdb_tables)
+	and ix.indisprimary = 'f'
+ORDER BY
+	t.relname,
+	i.relname
+
+mode unskip
+
+# get_table_comment
+statement ok
+SELECT
+	pgd.description as table_comment
+FROM
+	pg_catalog.pg_description pgd
+WHERE
+	pgd.objsubid = 0 AND
+	pgd.objoid = (SELECT MIN(table_oid) FROM duckdb_tables)
+
+
+statement ok
+CREATE TABLE check_constraint_tbl (
+	i INTEGER CHECK (i < 42)
+);
+
+# get_check_constraints
+query II
+SELECT
+	cons.conname as name,
+	pg_get_constraintdef(cons.oid) as src
+FROM
+	pg_catalog.pg_constraint cons
+WHERE
+	cons.contype = 'c'
+----
+CHECK((i < 42))	CHECK((i < 42))
+
+# load_enums
+query IIII
+SELECT t.typname as "name",
+	-- no enum defaults in 8.4 at least
+	-- t.typdefault as "default",
+	pg_catalog.pg_type_is_visible(t.oid) as "visible",
+	n.nspname as "schema",
+	e.enumlabel as "label"
+FROM pg_catalog.pg_type t
+		LEFT JOIN pg_catalog.pg_namespace n ON n.oid = t.typnamespace
+		LEFT JOIN pg_catalog.pg_enum e ON t.oid = e.enumtypid
+WHERE t.typtype = 'e' AND e.enumlabel IS NOT NULL
+ORDER BY e.enumsortorder
+----
+greeting	true	main	hi
+greeting	true	main	bonjour
+greeting	true	main	konnichiwa
+greeting	true	main	howdy
+
+# load domains
+statement ok
+SELECT t.typname as "name",
+	pg_catalog.format_type(t.typbasetype, t.typtypmod) as "attype",
+	not t.typnotnull as "nullable",
+	t.typdefault as "default",
+	pg_catalog.pg_type_is_visible(t.oid) as "visible",
+	n.nspname as "schema"
+FROM pg_catalog.pg_type t
+	LEFT JOIN pg_catalog.pg_namespace n ON n.oid = t.typnamespace
+WHERE t.typtype = 'd'

external/duckdb/test/sql/pg_catalog/system_functions.test

@@ -0,0 +1,98 @@
+# name: test/sql/pg_catalog/system_functions.test
+# description: Test various postgres' system functions (https://www.postgresql.org/docs/9.1/functions-info.html)
+# group: [pg_catalog]
+
+# avoid loading a storage database because it changes the initial database name
+query I
+SELECT CURRENT_USER
+----
+duckdb
+
+query I
+SELECT CURRENT_CATALOG
+----
+memory
+
+query I
+SELECT CURRENT_DATABASE()
+----
+memory
+
+query I
+SELECT pg_catalog.CURRENT_DATABASE()
+----
+memory
+
+query I
+SELECT USER
+----
+duckdb
+
+query I
+SELECT SESSION_USER
+----
+duckdb
+
+statement ok
+SELECT version();
+
+query I
+SELECT current_query();
+----
+SELECT current_query();
+
+query I
+SELECT pg_catalog.current_query();
+----
+SELECT pg_catalog.current_query();
+
+query IIII
+SELECT 1, 2, 3, current_query();
+----
+1	2	3	SELECT 1, 2, 3, current_query();
+
+query I
+SELECT current_schema();
+----
+main
+
+query I
+SELECT current_schemas(true);
+----
+[main, main, main, pg_catalog]
+
+query I
+SELECT current_schemas(false);
+----
+[]
+
+query IIII
+SELECT inet_client_addr(), inet_client_port(), inet_server_addr(), inet_server_port();
+----
+NULL	NULL	NULL	NULL
+
+statement ok
+select pg_postmaster_start_time();
+
+query I
+SELECT pg_is_other_temp_schema(33)
+----
+false
+
+query III
+SELECT col_description(0, 0), obj_description(0, 'duckdb'), shobj_description(0, 'duckdb');
+----
+NULL	NULL	NULL
+
+statement ok
+select txid_current();
+
+query I
+select pg_typeof(1);
+----
+integer
+
+statement error
+SELECT temp.current_user()
+----
+main.current_user