Subject: Re: Array of tuples as a parameter, with type casts
To: Vladimir Ryabtsev <greatvovan@gmail.com>
Cc: psycopg@lists.postgresql.org
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From: Adrian Klaver <adrian.klaver@aklaver.com>
Message-ID: <25c3598a-698f-8d0e-3659-791253b903ec@aklaver.com>
Date: Wed, 4 Dec 2019 10:44:47 -0800
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On 12/3/19 4:00 PM, Vladimir Ryabtsev wrote:
> It does not change much, the error message just says it now expects 
> 'character varying'.
> Anyway bigint problem is the next in the line.

Yeah it is related to this:

https://www.postgresql.org/docs/11/functions-array.html
unnest(anyarray) 	setof anyelement

Dealing with anyelement can be tricky.

I tried out an alternate solution:

json_query = "select * from json_to_recordset(%s) as t(a timestamp, b 
varchar, c bigint)"

cur.execute(json_query,[Json([{'a': datetime.now().isoformat(), 'b': 
'abc', 'c': 100},{'a': datetime.now().isoformat(), 'b': 'xyz', 'c': 200}])])

Which results in:

test_(postgres)# select * from json_to_recordset(E'[{"a": 
"2019-12-04T10:40:22.823910", "b": "abc", "c": 100}, {"a": 
"2019-12-04T10:40:22.823918", "b": "xyz", "c": 200}]') as t(a timestamp, 
b varchar, c bigint)
;
              a              |  b  |  c
----------------------------+-----+-----
  2019-12-04 10:40:22.82391  | abc | 100
  2019-12-04 10:40:22.823918 | xyz | 200
(2 rows)

> 
> --
> Regards,
> Vladimir


-- 
Adrian Klaver
adrian.klaver@aklaver.com