01.02.2017 17:41, Anastasia Lubennikova:
Now the simplest way to extract booleans and numbers from json/jsonb
is to cast it
to text and then cast to the appropriate type:
postgres=# select 'true'::jsonb::text::bool;
bool
------
t
postgres=# select '1.0'::jsonb::text::numeric;
numeric
---------
1.0
This patch implements direct casts from jsonb numeric (jbvNumeric) to
numeric, int4 and float8,
and from jsonb bool (jbvBool) to bool.
postgres=# select 'true'::jsonb::bool;
bool
------
t
postgres=# select '1.0'::jsonb::numeric;
numeric
---------
1.0
Waiting for your feedback.
If you find it useful, I can also add support of json and other types,
such as smallint and bigint.
I totally forgot about this thread, but it is a small but useful feature.
Maybe it's time to dust it off.
This patch was made by request of one of our clients,
and though they already use custom build, I think it would be better to
have these casts in core.
The patch is attached.
There are no tests yet, since I don't really sure what set of types do
we want to support.
Now the patch provides jsonb to numeric, int4, float8 and bool.
Also I have some doubts about castcontext. But 'explisit' seems to be
the correct one here.
--
Anastasia Lubennikova
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
commit 03b57ad50b9fe5bc785958bcf16badb58971d489
Author: Anastasia <a.lubennik...@postgrespro.ru>
Date: Wed Feb 28 21:14:31 2018 +0300
Cast jsonbNumeric to numeric, int4 and float8.
Cast jsonbBool to bool
diff --git a/src/backend/utils/adt/jsonb.c b/src/backend/utils/adt/jsonb.c
index 0f70180..3678dbe 100644
--- a/src/backend/utils/adt/jsonb.c
+++ b/src/backend/utils/adt/jsonb.c
@@ -1845,3 +1845,129 @@ jsonb_object_agg_finalfn(PG_FUNCTION_ARGS)
PG_RETURN_POINTER(out);
}
+
+Datum
+jsonb_numeric(PG_FUNCTION_ARGS)
+{
+ Jsonb *in = PG_GETARG_JSONB_P(0);
+ JsonbIterator *it;
+ JsonbValue v;
+
+ if (!JB_ROOT_IS_OBJECT(in)
+ && !(JB_ROOT_IS_ARRAY(in) && !JB_ROOT_IS_SCALAR(in)))
+ {
+ Assert(JB_ROOT_IS_SCALAR(in));
+
+ it = JsonbIteratorInit(&in->root);
+
+ /*
+ * A root scalar is stored as an array of one element, so we get the
+ * array and then its first (and only) member.
+ */
+ (void) JsonbIteratorNext(&it, &v, true);
+ Assert(v.type == jbvArray);
+ (void) JsonbIteratorNext(&it, &v, true);
+
+ if (v.type == jbvNumeric)
+ PG_RETURN_NUMERIC(v.val.numeric);
+ }
+
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("key value must be json numeric")));
+}
+
+Datum
+jsonb_int4(PG_FUNCTION_ARGS)
+{
+ Jsonb *in = PG_GETARG_JSONB_P(0);
+ JsonbIterator *it;
+ JsonbValue v;
+
+ if (!JB_ROOT_IS_OBJECT(in)
+ && !(JB_ROOT_IS_ARRAY(in) && !JB_ROOT_IS_SCALAR(in)))
+ {
+ Assert(JB_ROOT_IS_SCALAR(in));
+
+ it = JsonbIteratorInit(&in->root);
+
+ /*
+ * A root scalar is stored as an array of one element, so we get the
+ * array and then its first (and only) member.
+ */
+ (void) JsonbIteratorNext(&it, &v, true);
+ Assert(v.type == jbvArray);
+ (void) JsonbIteratorNext(&it, &v, true);
+
+ if (v.type == jbvNumeric)
+ PG_RETURN_INT32(DatumGetInt32(DirectFunctionCall1(numeric_int4,
+ NumericGetDatum(v.val.numeric))));
+ }
+
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("key value must be json numeric")));
+}
+
+Datum
+jsonb_float8(PG_FUNCTION_ARGS)
+{
+ Jsonb *in = PG_GETARG_JSONB_P(0);
+ JsonbIterator *it;
+ JsonbValue v;
+
+ if (!JB_ROOT_IS_OBJECT(in)
+ && !(JB_ROOT_IS_ARRAY(in) && !JB_ROOT_IS_SCALAR(in)))
+ {
+ Assert(JB_ROOT_IS_SCALAR(in));
+
+ it = JsonbIteratorInit(&in->root);
+
+ /*
+ * A root scalar is stored as an array of one element, so we get the
+ * array and then its first (and only) member.
+ */
+ (void) JsonbIteratorNext(&it, &v, true);
+ Assert(v.type == jbvArray);
+ (void) JsonbIteratorNext(&it, &v, true);
+
+ if (v.type == jbvNumeric)
+ PG_RETURN_FLOAT8(DatumGetFloat8(DirectFunctionCall1(numeric_float8,
+ NumericGetDatum(v.val.numeric))));
+ }
+
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("key value must be json numeric")));
+}
+
+Datum
+jsonb_bool(PG_FUNCTION_ARGS)
+{
+ Jsonb *in = PG_GETARG_JSONB_P(0);
+ JsonbIterator *it;
+ JsonbValue v;
+
+ if (!JB_ROOT_IS_OBJECT(in)
+ && !(JB_ROOT_IS_ARRAY(in) && !JB_ROOT_IS_SCALAR(in)))
+ {
+ Assert(JB_ROOT_IS_SCALAR(in));
+
+ it = JsonbIteratorInit(&in->root);
+
+ /*
+ * A root scalar is stored as an array of one element, so we get the
+ * array and then its first (and only) member.
+ */
+ (void) JsonbIteratorNext(&it, &v, true);
+ Assert(v.type == jbvArray);
+ (void) JsonbIteratorNext(&it, &v, true);
+
+ if (v.type == jbvBool)
+ PG_RETURN_BOOL(v.val.boolean);
+ }
+
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("key value must be json boolean")));
+}
diff --git a/src/include/catalog/pg_cast.h b/src/include/catalog/pg_cast.h
index b447818..ea765df 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 c00d055..2f84978 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2477,6 +2477,15 @@ DESCR("convert int2 to numeric");
DATA(insert OID = 1783 ( int2 PGNSP PGUID 12 1 0 0 0 f 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 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 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 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 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 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/include/utils/builtins.h b/src/include/utils/builtins.h
index 3e462f1..2b01f17 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -128,4 +128,10 @@ extern int32 type_maximum_size(Oid type_oid, int32 typemod);
/* quote.c */
extern char *quote_literal_cstr(const char *rawstr);
+/* jsonb.c */
+extern Datum jsonb_numeric(PG_FUNCTION_ARGS);
+extern Datum jsonb_int4(PG_FUNCTION_ARGS);
+extern Datum jsonb_float8(PG_FUNCTION_ARGS);
+extern Datum jsonb_bool(PG_FUNCTION_ARGS);
+
#endif /* BUILTINS_H */
