[GENERAL] How to stop array_to_json from interpolating column names thatweren't there
9.6
I’ve a view that shows information about schemas:
SELECT schemata.catalog_name,
schemata.schema_name,
('/'::text || (schemata.schema_name)::text) AS schema_name_address
FROM information_schema.schemata
ORDER BY schemata.catalog_name, schemata.schema_name
Fine. I now want to turn that result set into a JSON array. I can do this:
SELECT
ARRAY_AGG(foo) AS foos
FROM (
SELECT
row_to_json(schemata_)
FROM
schemata_)
AS
foo
and I get this:
{“(\”{\"\"catalog_name\"\":\"\"ds2_development\"\",\"\"schema_name\"\":\"\"admin\"\",\"\"schema_name_address\"\":\"\"/admin\"\"}\")","(\"…
which is great. I have an array of perfect JSON objects. Now I just need to turn that into a single JSON object. But when I do the obvious:
SELECT array_to_json(SELECTARRAY_AGG(foo) AS foosFROM (SELECTrow_to_json(schemata_)FROMschemata_)ASfoo)
I get a syntax error. And when I do:
SELECT TO_JSON(foos) FROM (
SELECT
ARRAY_AGG(foo) AS foos
FROM (
SELECT
row_to_json(schemata_)
FROM
schemata_)
AS
foo
) AS bar
Postgres tries to be helpful by interpolating a column name I don’t want (here, row_to_json):
[{“row_to_json":{"catalog_name":"ds2_development","schema_name":"admin","schema_name_address":"/admin"}},{"row_to_json":{"catalog_name":"ds2_development","schema_name":"anon","schema_name_address":"/anon"}},{"row_to_json":
…
I could fix this in PLV8 a tad inefficiently, but I feel like I ought to be able to do this in pure SQL and there’s some heuristic or Yet Another Weird Corner Case I’m as yet unaware of.
So: can I do this in SQL? How?
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