diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 8debb8cbbcc..a072b976161 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -13050,30 +13050,72 @@ table2-mapping - - While the examples for the functions - json_populate_record, - json_populate_recordset, - json_to_record and - json_to_recordset use constants, the typical use - would be to reference a table in the FROM clause - and use one of its json or jsonb columns - as an argument to the function. Extracted key values can then be - referenced in other parts of the query, like WHERE - clauses and target lists. Extracting multiple values in this - way can improve performance over extracting them separately with - per-key operators. - + + The functions + json[b]_populate_record, + json[b]_populate_recordset, + json[b]_to_record and + json[b]_to_recordset + operate on a JSON object, or array of objects, and extract the values + associated with keys whose names match column names of the output row + type. + Object fields that do not correspond to any output column name are + ignored, and output columns that do not match any object field will be + filled with nulls. + To convert a JSON value to the SQL type of an output column, the + following rules are applied in sequence: + + + + A JSON null value is converted to a SQL null in all cases. + + + + + If the output column is of type json + or jsonb, the JSON value is just reproduced exactly. + + + + + If the output column is a composite (row) type, and the JSON value is + a JSON object, the fields of the object are converted to columns of + the output row type by recursive application of these rules. + + + + + Likewise, if the output column is an array type and the JSON value is + a JSON array, the elements of the JSON array are converted to elements + of the output array by recursive application of these rules. + + + + + Otherwise, if the JSON value is a string literal, the contents of the + string are fed to the input conversion function for the column's data + type. + + + + + Otherwise, the ordinary text representation of the JSON value is fed + to the input conversion function for the column's data type. + + + + - - JSON keys are matched to identical column names in the target - row type. JSON type coercion for these functions is best - effort and may not result in desired values for some types. - JSON fields that do not appear in the target row type will be - omitted from the output, and target columns that do not match any - JSON field will simply be NULL. - - + + While the examples for these functions use constants, the typical use + would be to reference a table in the FROM clause + and use one of its json or jsonb columns + as an argument to the function. Extracted key values can then be + referenced in other parts of the query, like WHERE + clauses and target lists. Extracting multiple values in this + way can improve performance over extracting them separately with + per-key operators. + diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c index 28bdc7243fd..9e7035c71a1 100644 --- a/src/backend/utils/adt/jsonfuncs.c +++ b/src/backend/utils/adt/jsonfuncs.c @@ -2803,26 +2803,7 @@ populate_scalar(ScalarIOData *io, Oid typid, int32 typmod, JsValue *jsv) json = jsv->val.json.str; Assert(json); - - /* already done the hard work in the json case */ - if ((typid == JSONOID || typid == JSONBOID) && - jsv->val.json.type == JSON_TOKEN_STRING) - { - /* - * Add quotes around string value (should be already escaped) if - * converting to json/jsonb. - */ - - if (len < 0) - len = strlen(json); - - str = palloc(len + sizeof(char) * 3); - str[0] = '"'; - memcpy(&str[1], json, len); - str[len + 1] = '"'; - str[len + 2] = '\0'; - } - else if (len >= 0) + if (len >= 0) { /* Need to copy non-null-terminated string */ str = palloc(len + 1 * sizeof(char)); @@ -2830,7 +2811,21 @@ populate_scalar(ScalarIOData *io, Oid typid, int32 typmod, JsValue *jsv) str[len] = '\0'; } else - str = json; /* null-terminated string */ + str = json; /* string is already null-terminated */ + + /* If converting to json/jsonb, make string into valid JSON literal */ + if ((typid == JSONOID || typid == JSONBOID) && + jsv->val.json.type == JSON_TOKEN_STRING) + { + StringInfoData buf; + + initStringInfo(&buf); + escape_json(&buf, str); + /* free temporary buffer */ + if (str != json) + pfree(str); + str = buf.data; + } } else { diff --git a/src/test/regress/expected/json.out b/src/test/regress/expected/json.out index cb935980394..5b8e67784f5 100644 --- a/src/test/regress/expected/json.out +++ b/src/test/regress/expected/json.out @@ -2276,6 +2276,42 @@ select * from json_to_record('{"ia2": [[[1], [2], [3]]]}') as x(ia2 int4[][]); {{{1},{2},{3}}} (1 row) +select * from json_to_record('{"out": {"key": 1}}') as x(out json); + out +------------ + {"key": 1} +(1 row) + +select * from json_to_record('{"out": [{"key": 1}]}') as x(out json); + out +-------------- + [{"key": 1}] +(1 row) + +select * from json_to_record('{"out": "{\"key\": 1}"}') as x(out json); + out +---------------- + "{\"key\": 1}" +(1 row) + +select * from json_to_record('{"out": {"key": 1}}') as x(out jsonb); + out +------------ + {"key": 1} +(1 row) + +select * from json_to_record('{"out": [{"key": 1}]}') as x(out jsonb); + out +-------------- + [{"key": 1}] +(1 row) + +select * from json_to_record('{"out": "{\"key\": 1}"}') as x(out jsonb); + out +---------------- + "{\"key\": 1}" +(1 row) + -- json_strip_nulls select json_strip_nulls(null); json_strip_nulls diff --git a/src/test/regress/expected/jsonb.out b/src/test/regress/expected/jsonb.out index 10183030068..469079c5d8f 100644 --- a/src/test/regress/expected/jsonb.out +++ b/src/test/regress/expected/jsonb.out @@ -2652,6 +2652,42 @@ select * from jsonb_to_record('{"ia2": [[[1], [2], [3]]]}') as x(ia2 int4[][]); {{{1},{2},{3}}} (1 row) +select * from jsonb_to_record('{"out": {"key": 1}}') as x(out json); + out +------------ + {"key": 1} +(1 row) + +select * from jsonb_to_record('{"out": [{"key": 1}]}') as x(out json); + out +-------------- + [{"key": 1}] +(1 row) + +select * from jsonb_to_record('{"out": "{\"key\": 1}"}') as x(out json); + out +---------------- + "{\"key\": 1}" +(1 row) + +select * from jsonb_to_record('{"out": {"key": 1}}') as x(out jsonb); + out +------------ + {"key": 1} +(1 row) + +select * from jsonb_to_record('{"out": [{"key": 1}]}') as x(out jsonb); + out +-------------- + [{"key": 1}] +(1 row) + +select * from jsonb_to_record('{"out": "{\"key\": 1}"}') as x(out jsonb); + out +---------------- + "{\"key\": 1}" +(1 row) + -- test type info caching in jsonb_populate_record() CREATE TEMP TABLE jsbpoptest (js jsonb); INSERT INTO jsbpoptest diff --git a/src/test/regress/sql/json.sql b/src/test/regress/sql/json.sql index 0f0a32e2a0e..a52beaa27a1 100644 --- a/src/test/regress/sql/json.sql +++ b/src/test/regress/sql/json.sql @@ -742,6 +742,13 @@ select * from json_to_record('{"ia2": [1, 2, 3]}') as x(ia2 int[][]); select * from json_to_record('{"ia2": [[1, 2], [3, 4]]}') as x(ia2 int4[][]); select * from json_to_record('{"ia2": [[[1], [2], [3]]]}') as x(ia2 int4[][]); +select * from json_to_record('{"out": {"key": 1}}') as x(out json); +select * from json_to_record('{"out": [{"key": 1}]}') as x(out json); +select * from json_to_record('{"out": "{\"key\": 1}"}') as x(out json); +select * from json_to_record('{"out": {"key": 1}}') as x(out jsonb); +select * from json_to_record('{"out": [{"key": 1}]}') as x(out jsonb); +select * from json_to_record('{"out": "{\"key\": 1}"}') as x(out jsonb); + -- json_strip_nulls select json_strip_nulls(null); diff --git a/src/test/regress/sql/jsonb.sql b/src/test/regress/sql/jsonb.sql index c1a7880792d..ba870872e80 100644 --- a/src/test/regress/sql/jsonb.sql +++ b/src/test/regress/sql/jsonb.sql @@ -709,6 +709,13 @@ select * from jsonb_to_record('{"ia2": [1, 2, 3]}') as x(ia2 int[][]); select * from jsonb_to_record('{"ia2": [[1, 2], [3, 4]]}') as x(ia2 int4[][]); select * from jsonb_to_record('{"ia2": [[[1], [2], [3]]]}') as x(ia2 int4[][]); +select * from jsonb_to_record('{"out": {"key": 1}}') as x(out json); +select * from jsonb_to_record('{"out": [{"key": 1}]}') as x(out json); +select * from jsonb_to_record('{"out": "{\"key\": 1}"}') as x(out json); +select * from jsonb_to_record('{"out": {"key": 1}}') as x(out jsonb); +select * from jsonb_to_record('{"out": [{"key": 1}]}') as x(out jsonb); +select * from jsonb_to_record('{"out": "{\"key\": 1}"}') as x(out jsonb); + -- test type info caching in jsonb_populate_record() CREATE TEMP TABLE jsbpoptest (js jsonb);