SQL/JSON: Fix JSON_TABLE() column deparsing

The deparsing code in get_json_expr_options() unnecessarily emitted
the default column-specific ON ERROR / EMPTY behavior when the
top-level ON ERROR behavior in JSON_TABLE was set to ERROR. Fix that
by not overriding the column-specific default, determined based on
the column's JsonExprOp in get_json_table_columns(), with
JSON_BEHAVIOR_ERROR when that is the top-level ON ERROR behavior.

Note that this only removes redundancy; the current deparsing output
is not incorrect, just redundant.

Reviewed-by: Jian He <jian.universality@gmail.com>
Discussion: https://postgr.es/m/CACJufxEo4sUjKCYtda0_qt9tazqqKPmF1cqhW9KBOUeJFqQd2g@mail.gmail.com
Backpatch-through: 17
This commit is contained in:
Amit Langote 2024-09-06 13:25:02 +09:00
parent 4d7e24e0f4
commit ee75a03f37
3 changed files with 37 additions and 4 deletions

View File

@ -11719,7 +11719,6 @@ get_json_table_columns(TableFunc *tf, JsonTablePathScan *scan,
bool showimplicit)
{
StringInfo buf = context->buf;
JsonExpr *jexpr = castNode(JsonExpr, tf->docexpr);
ListCell *lc_colname;
ListCell *lc_coltype;
ListCell *lc_coltypmod;
@ -11772,6 +11771,10 @@ get_json_table_columns(TableFunc *tf, JsonTablePathScan *scan,
if (ordinality)
continue;
/*
* Set default_behavior to guide get_json_expr_options() on whether to
* to emit the ON ERROR / EMPTY clauses.
*/
if (colexpr->op == JSON_EXISTS_OP)
{
appendStringInfoString(buf, " EXISTS");
@ -11795,9 +11798,6 @@ get_json_table_columns(TableFunc *tf, JsonTablePathScan *scan,
default_behavior = JSON_BEHAVIOR_NULL;
}
if (jexpr->on_error->btype == JSON_BEHAVIOR_ERROR)
default_behavior = JSON_BEHAVIOR_ERROR;
appendStringInfoString(buf, " PATH ");
get_json_path_spec(colexpr->path_spec, context, showimplicit);

View File

@ -1132,3 +1132,26 @@ ERROR: invalid ON ERROR behavior for column "a"
LINE 1: ...M JSON_TABLE(jsonb '1', '$' COLUMNS (a int exists empty obje...
^
DETAIL: Only ERROR, TRUE, FALSE, or UNKNOWN is allowed in ON ERROR for EXISTS columns.
-- Test JSON_TABLE() column deparsing -- don't emit default ON ERROR / EMPTY
-- behavior
CREATE VIEW json_table_view8 AS SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a text PATH '$'));
\sv json_table_view8;
CREATE OR REPLACE VIEW public.json_table_view8 AS
SELECT a
FROM JSON_TABLE(
'"a"'::text, '$' AS json_table_path_0
COLUMNS (
a text PATH '$'
)
)
CREATE VIEW json_table_view9 AS SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a text PATH '$') ERROR ON ERROR);
\sv json_table_view9;
CREATE OR REPLACE VIEW public.json_table_view9 AS
SELECT a
FROM JSON_TABLE(
'"a"'::text, '$' AS json_table_path_0
COLUMNS (
a text PATH '$'
) ERROR ON ERROR
)
DROP VIEW json_table_view8, json_table_view9;

View File

@ -542,3 +542,13 @@ SELECT * FROM JSON_TABLE(jsonb '1', '$' COLUMNS (a int) NULL ON ERROR);
SELECT * FROM JSON_TABLE(jsonb '1', '$' COLUMNS (a int true on empty));
SELECT * FROM JSON_TABLE(jsonb '1', '$' COLUMNS (a int omit quotes true on error));
SELECT * FROM JSON_TABLE(jsonb '1', '$' COLUMNS (a int exists empty object on error));
-- Test JSON_TABLE() column deparsing -- don't emit default ON ERROR / EMPTY
-- behavior
CREATE VIEW json_table_view8 AS SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a text PATH '$'));
\sv json_table_view8;
CREATE VIEW json_table_view9 AS SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a text PATH '$') ERROR ON ERROR);
\sv json_table_view9;
DROP VIEW json_table_view8, json_table_view9;