mirror of https://github.com/postgres/postgres
Add json_array_elements_text function.
This was a notable omission from the json functions added in 9.3 and there have been numerous complaints about its absence. Laurence Rowe.
This commit is contained in:
Andrew Dunstan
parent
699b1f40da
commit
5264d91541
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@ -10280,6 +10280,27 @@ table2-mapping
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1
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true
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[2,false]
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</programlisting>
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</entry>
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</row>
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<row>
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<entry>
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<indexterm>
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<primary>json_array_elements_text</primary>
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</indexterm>
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<literal>json_array_elements_text(json)</literal>
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</entry>
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<entry><type>SETOF json</type></entry>
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<entry>
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Expands a JSON array to a set of text values.
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</entry>
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<entry><literal>json_array_elements_text('["foo", "bar"]')</literal></entry>
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<entry>
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<programlisting>
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value
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-----------
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foo
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bar
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</programlisting>
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</entry>
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</row>
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@ -66,6 +66,9 @@ static void each_object_field_end(void *state, char *fname, bool isnull);
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static void each_array_start(void *state);
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static void each_scalar(void *state, char *token, JsonTokenType tokentype);
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/* common worker for json_each* functions */
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static inline Datum elements_worker(PG_FUNCTION_ARGS, bool as_text);
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/* semantic action functions for json_array_elements */
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static void elements_object_start(void *state);
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static void elements_array_element_start(void *state, bool isnull);
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@ -165,6 +168,9 @@ typedef struct ElementsState
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TupleDesc ret_tdesc;
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MemoryContext tmp_cxt;
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char *result_start;
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bool normalize_results;
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bool next_scalar;
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char *normalized_scalar;
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} ElementsState;
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/* state for get_json_object_as_hash */
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@ -1069,7 +1075,7 @@ each_scalar(void *state, char *token, JsonTokenType tokentype)
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}
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/*
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* SQL function json_array_elements
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* SQL functions json_array_elements and json_array_elements_text
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*
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* get the elements from a json array
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*
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@ -1077,11 +1083,23 @@ each_scalar(void *state, char *token, JsonTokenType tokentype)
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*/
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Datum
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json_array_elements(PG_FUNCTION_ARGS)
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{
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return elements_worker(fcinfo, false);
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}
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Datum
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json_array_elements_text(PG_FUNCTION_ARGS)
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{
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return elements_worker(fcinfo, true);
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}
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static inline Datum
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elements_worker(PG_FUNCTION_ARGS, bool as_text)
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{
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text *json = PG_GETARG_TEXT_P(0);
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/* elements doesn't need any escaped strings, so use false here */
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JsonLexContext *lex = makeJsonLexContext(json, false);
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/* elements only needs escaped strings when as_text */
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JsonLexContext *lex = makeJsonLexContext(json, as_text);
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JsonSemAction *sem;
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ReturnSetInfo *rsi;
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MemoryContext old_cxt;
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@ -1124,6 +1142,9 @@ json_array_elements(PG_FUNCTION_ARGS)
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sem->array_element_start = elements_array_element_start;
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sem->array_element_end = elements_array_element_end;
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state->normalize_results = as_text;
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state->next_scalar = false;
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state->lex = lex;
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state->tmp_cxt = AllocSetContextCreate(CurrentMemoryContext,
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"json_array_elements temporary cxt",
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@ -1146,7 +1167,17 @@ elements_array_element_start(void *state, bool isnull)
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/* save a pointer to where the value starts */
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if (_state->lex->lex_level == 1)
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_state->result_start = _state->lex->token_start;
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{
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/*
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* next_scalar will be reset in the array_element_end handler, and
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* since we know the value is a scalar there is no danger of it being
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* on while recursing down the tree.
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*/
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if (_state->normalize_results && _state->lex->token_type == JSON_TOKEN_STRING)
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_state->next_scalar = true;
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else
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_state->result_start = _state->lex->token_start;
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}
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}
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static void
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@ -1158,7 +1189,7 @@ elements_array_element_end(void *state, bool isnull)
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text *val;
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HeapTuple tuple;
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Datum values[1];
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static bool nulls[1] = {false};
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bool nulls[1] = {false};
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/* skip over nested objects */
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if (_state->lex->lex_level != 1)
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@ -1167,10 +1198,23 @@ elements_array_element_end(void *state, bool isnull)
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/* use the tmp context so we can clean up after each tuple is done */
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old_cxt = MemoryContextSwitchTo(_state->tmp_cxt);
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len = _state->lex->prev_token_terminator - _state->result_start;
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val = cstring_to_text_with_len(_state->result_start, len);
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if (isnull && _state->normalize_results)
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{
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nulls[0] = true;
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values[0] = (Datum) NULL;
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}
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else if (_state->next_scalar)
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{
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values[0] = CStringGetTextDatum(_state->normalized_scalar);
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_state->next_scalar = false;
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}
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else
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{
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len = _state->lex->prev_token_terminator - _state->result_start;
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val = cstring_to_text_with_len(_state->result_start, len);
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values[0] = PointerGetDatum(val);
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}
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values[0] = PointerGetDatum(val);
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tuple = heap_form_tuple(_state->ret_tdesc, values, nulls);
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@ -1204,10 +1248,9 @@ elements_scalar(void *state, char *token, JsonTokenType tokentype)
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("cannot call json_array_elements on a scalar")));
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/*
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* json_array_elements always returns json, so there's no need to think
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* about de-escaped values here.
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*/
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/* supply de-escaped value if required */
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if (_state->next_scalar)
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_state->normalized_scalar = token;
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}
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/*
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@ -4185,6 +4185,8 @@ DATA(insert OID = 3205 ( json_to_recordset PGNSP PGUID 12 1 100 0 0 f f f f f
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DESCR("get set of records with fields from a json array of objects");
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DATA(insert OID = 3968 ( json_typeof PGNSP PGUID 12 1 0 0 0 f f f f t f i 1 0 25 "114" _null_ _null_ _null_ _null_ json_typeof _null_ _null_ _null_ ));
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DESCR("get the type of a json value");
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DATA(insert OID = 3969 ( json_array_elements_text PGNSP PGUID 12 1 100 0 0 f f f f t t i 1 0 25 "114" "{114,25}" "{i,o}" "{from_json,value}" _null_ json_array_elements_text _null_ _null_ _null_ ));
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DESCR("elements of json array");
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/* uuid */
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DATA(insert OID = 2952 ( uuid_in PGNSP PGUID 12 1 0 0 0 f f f f t f i 1 0 2950 "2275" _null_ _null_ _null_ _null_ uuid_in _null_ _null_ _null_ ));
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@ -58,6 +58,7 @@ extern Datum json_array_length(PG_FUNCTION_ARGS);
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extern Datum json_each(PG_FUNCTION_ARGS);
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extern Datum json_each_text(PG_FUNCTION_ARGS);
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extern Datum json_array_elements(PG_FUNCTION_ARGS);
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extern Datum json_array_elements_text(PG_FUNCTION_ARGS);
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extern Datum json_populate_record(PG_FUNCTION_ARGS);
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extern Datum json_populate_recordset(PG_FUNCTION_ARGS);
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extern Datum json_to_record(PG_FUNCTION_ARGS);
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@ -801,7 +801,7 @@ select '{"f2":["f3",1],"f4":{"f5":99,"f6":"stringy"}}'::json#>>'{f2,1}';
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(1 row)
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-- array_elements
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select json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false]');
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select json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false,"stringy"]');
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json_array_elements
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-----------------------
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1
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@ -810,9 +810,10 @@ select json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false]'
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null
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{"f1":1,"f2":[7,8,9]}
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false
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(6 rows)
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"stringy"
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(7 rows)
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select * from json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false]') q;
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select * from json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false,"stringy"]') q;
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value
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-----------------------
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1
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@ -821,7 +822,32 @@ select * from json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},
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null
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{"f1":1,"f2":[7,8,9]}
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false
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(6 rows)
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"stringy"
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(7 rows)
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select json_array_elements_text('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false,"stringy"]');
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json_array_elements_text
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--------------------------
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1
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true
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[1,[2,3]]
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{"f1":1,"f2":[7,8,9]}
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false
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stringy
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(7 rows)
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select * from json_array_elements_text('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false,"stringy"]') q;
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value
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-----------------------
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1
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true
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[1,[2,3]]
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{"f1":1,"f2":[7,8,9]}
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false
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stringy
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(7 rows)
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-- populate_record
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create type jpop as (a text, b int, c timestamp);
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@ -801,7 +801,7 @@ select '{"f2":["f3",1],"f4":{"f5":99,"f6":"stringy"}}'::json#>>'{f2,1}';
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(1 row)
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-- array_elements
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select json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false]');
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select json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false,"stringy"]');
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json_array_elements
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-----------------------
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1
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@ -810,9 +810,10 @@ select json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false]'
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null
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{"f1":1,"f2":[7,8,9]}
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false
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(6 rows)
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"stringy"
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(7 rows)
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select * from json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false]') q;
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select * from json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false,"stringy"]') q;
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value
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-----------------------
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1
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@ -821,7 +822,32 @@ select * from json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},
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null
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{"f1":1,"f2":[7,8,9]}
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false
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(6 rows)
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"stringy"
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(7 rows)
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select json_array_elements_text('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false,"stringy"]');
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json_array_elements_text
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--------------------------
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1
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true
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[1,[2,3]]
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{"f1":1,"f2":[7,8,9]}
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false
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stringy
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(7 rows)
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select * from json_array_elements_text('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false,"stringy"]') q;
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value
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-----------------------
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1
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true
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[1,[2,3]]
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{"f1":1,"f2":[7,8,9]}
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false
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stringy
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(7 rows)
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-- populate_record
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create type jpop as (a text, b int, c timestamp);
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@ -265,8 +265,10 @@ select '{"f2":["f3",1],"f4":{"f5":99,"f6":"stringy"}}'::json#>>'{f2,1}';
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-- array_elements
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select json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false]');
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select * from json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false]') q;
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select json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false,"stringy"]');
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select * from json_array_elements('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false,"stringy"]') q;
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select json_array_elements_text('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false,"stringy"]');
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select * from json_array_elements_text('[1,true,[1,[2,3]],null,{"f1":1,"f2":[7,8,9]},false,"stringy"]') q;
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-- populate_record
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create type jpop as (a text, b int, c timestamp);
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