diff --git a/src/backend/utils/adt/jsonb.c b/src/backend/utils/adt/jsonb.c
index 0f70180164..fb907f2a73 100644
--- a/src/backend/utils/adt/jsonb.c
+++ b/src/backend/utils/adt/jsonb.c
@@ -1845,3 +1845,98 @@ jsonb_object_agg_finalfn(PG_FUNCTION_ARGS)
 
 	PG_RETURN_POINTER(out);
 }
+
+
+/*
+ * Extract scalar value from raw-scalar pseudo-array jsonb.
+ */
+static JsonbValue *
+JsonbExtractScalar(JsonbContainer *jbc, JsonbValue *res)
+{
+	JsonbIterator *it;
+	JsonbIteratorToken tok PG_USED_FOR_ASSERTS_ONLY;
+	JsonbValue	tmp;
+
+	if (!JsonContainerIsArray(jbc) || !JsonContainerIsScalar(jbc))
+		return NULL;
+
+	/*
+	 * A root scalar is stored as an array of one element, so we get the
+	 * array and then its first (and only) member.
+	 */
+	it = JsonbIteratorInit(jbc);
+
+	tok = JsonbIteratorNext(&it, &tmp, true);
+	Assert(tok == WJB_BEGIN_ARRAY);
+	Assert(tmp.val.array.nElems == 1 && tmp.val.array.rawScalar);
+
+	tok = JsonbIteratorNext(&it, res, true);
+	Assert (tok == WJB_ELEM);
+	Assert(IsAJsonbScalar(res));
+
+	tok = JsonbIteratorNext(&it, &tmp, true);
+	Assert (tok == WJB_END_ARRAY);
+
+	tok = JsonbIteratorNext(&it, &tmp, true);
+	Assert(tok == WJB_DONE);
+
+	return res;
+}
+
+Datum
+jsonb_numeric(PG_FUNCTION_ARGS)
+{
+	Jsonb	   *in = PG_GETARG_JSONB_P(0);
+	JsonbValue	v;
+
+	if (!JsonbExtractScalar(&in->root, &v) || v.type != jbvNumeric)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("jsonb value must be numeric")));
+
+	PG_RETURN_NUMERIC(v.val.numeric);
+}
+
+Datum
+jsonb_int4(PG_FUNCTION_ARGS)
+{
+	Jsonb	   *in = PG_GETARG_JSONB_P(0);
+	JsonbValue  v;
+
+	if (!JsonbExtractScalar(&in->root, &v) || v.type != jbvNumeric)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("jsonb value must be numeric")));
+
+	PG_RETURN_INT32(DatumGetInt32(DirectFunctionCall1(numeric_int4,
+								  NumericGetDatum(v.val.numeric))));
+}
+
+Datum
+jsonb_float8(PG_FUNCTION_ARGS)
+{
+	Jsonb	   *in = PG_GETARG_JSONB_P(0);
+	JsonbValue	v;
+
+	if (!JsonbExtractScalar(&in->root, &v) || v.type != jbvNumeric)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("jsonb value must be numeric")));
+
+	PG_RETURN_FLOAT8(DatumGetFloat8(DirectFunctionCall1(numeric_float8,
+									NumericGetDatum(v.val.numeric))));
+}
+
+Datum
+jsonb_bool(PG_FUNCTION_ARGS)
+{
+	Jsonb	   *in = PG_GETARG_JSONB_P(0);
+	JsonbValue	v;
+
+	if (!JsonbExtractScalar(&in->root, &v) || v.type != jbvBool)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("jsonb value must be boolean")));
+
+	PG_RETURN_BOOL(v.val.boolean);
+}
diff --git a/src/include/catalog/pg_cast.h b/src/include/catalog/pg_cast.h
index b4478188ca..ea765df80e 100644
--- a/src/include/catalog/pg_cast.h
+++ b/src/include/catalog/pg_cast.h
@@ -391,5 +391,10 @@ DATA(insert ( 1700 1700 1703 i f ));
 /* json to/from jsonb */
 DATA(insert (  114 3802    0 a i ));
 DATA(insert ( 3802	114    0 a i ));
+/* jsonb to numeric types */
+DATA(insert ( 3802	1700   4001 e f ));
+DATA(insert ( 3802	23     4002 e f ));
+DATA(insert ( 3802	701    4003 e f ));
+DATA(insert ( 3802	16     4004 e f ));
 
 #endif							/* PG_CAST_H */
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index bfc90098f8..0d5d33985d 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2475,6 +2475,16 @@ DESCR("convert int2 to numeric");
 DATA(insert OID = 1783 ( int2					PGNSP PGUID 12 1 0 0 0 f f f t f i s 1 0 21 "1700" _null_ _null_ _null_ _null_ _null_ numeric_int2 _null_ _null_ _null_ ));
 DESCR("convert numeric to int2");
 
+
+DATA(insert OID = 4001 ( numeric			PGNSP PGUID 12 1 0 0 0 f f f t f i s 1 0 1700 "3802" _null_ _null_ _null_ _null_ _null_ jsonb_numeric  _null_ _null_ _null_ ));
+DESCR("convert jsonb to numeric");
+DATA(insert OID = 4002 ( int4				PGNSP PGUID 12 1 0 0 0 f f f t f i s 1 0 23 "3802" _null_ _null_ _null_ _null_ _null_ jsonb_int4  _null_ _null_ _null_ ));
+DESCR("convert jsonb to int4");
+DATA(insert OID = 4003 ( float8			PGNSP PGUID 12 1 0 0 0 f f f t f i s 1 0 701 "3802" _null_ _null_ _null_ _null_ _null_ jsonb_float8  _null_ _null_ _null_ ));
+DESCR("convert jsonb to float8");
+DATA(insert OID = 4004 ( bool			PGNSP PGUID 12 1 0 0 0 f f f t f i s 1 0 16 "3802" _null_ _null_ _null_ _null_ _null_ jsonb_bool  _null_ _null_ _null_ ));
+DESCR("convert jsonb to boolean");
+
 /* formatting */
 DATA(insert OID = 1770 ( to_char			PGNSP PGUID 12 1 0 0 0 f f f t f s s 2 0 25 "1184 25" _null_ _null_ _null_ _null_  _null_ timestamptz_to_char _null_ _null_ _null_ ));
 DESCR("format timestamp with time zone to text");
diff --git a/src/test/regress/expected/jsonb.out b/src/test/regress/expected/jsonb.out
index 465195a317..f577ad6aa5 100644
--- a/src/test/regress/expected/jsonb.out
+++ b/src/test/regress/expected/jsonb.out
@@ -4191,3 +4191,36 @@ select ts_headline('[]'::jsonb, tsquery('aaa & bbb'));
  []
 (1 row)
 
+-- casts
+select 'true'::jsonb::bool;
+ bool 
+------
+ t
+(1 row)
+
+select '[]'::jsonb::bool;
+ERROR:  jsonb value must be boolean
+select '1.0'::jsonb::float;
+ float8 
+--------
+      1
+(1 row)
+
+select '[1.0]'::jsonb::float;
+ERROR:  jsonb value must be numeric
+select '12345'::jsonb::int4;
+ int4  
+-------
+ 12345
+(1 row)
+
+select '"hello"'::jsonb::int4;
+ERROR:  jsonb value must be numeric
+select '12345'::jsonb::numeric;
+ numeric 
+---------
+   12345
+(1 row)
+
+select '{}'::jsonb::numeric;
+ERROR:  jsonb value must be numeric
diff --git a/src/test/regress/sql/jsonb.sql b/src/test/regress/sql/jsonb.sql
index 903e5ef67d..9c2158f8c6 100644
--- a/src/test/regress/sql/jsonb.sql
+++ b/src/test/regress/sql/jsonb.sql
@@ -1105,3 +1105,13 @@ select ts_headline('english', '{"a": "aaa bbb", "b": {"c": "ccc ddd fff", "c1":
 select ts_headline('null'::jsonb, tsquery('aaa & bbb'));
 select ts_headline('{}'::jsonb, tsquery('aaa & bbb'));
 select ts_headline('[]'::jsonb, tsquery('aaa & bbb'));
+
+-- casts
+select 'true'::jsonb::bool;
+select '[]'::jsonb::bool;
+select '1.0'::jsonb::float;
+select '[1.0]'::jsonb::float;
+select '12345'::jsonb::int4;
+select '"hello"'::jsonb::int4;
+select '12345'::jsonb::numeric;
+select '{}'::jsonb::numeric;