On 04/08/2018 08:44 PM, Đỗ Ngọc Trí Cường wrote:
Dear Arian Klaver,

I think there is a misunderstood here.

I think that I quite understand how is the second query run.

The question I asked here is why exporting data, which is generated by a query "JSON_AGG" , with command "COPY". The data contain "\n" as 2 characters instead of "new line" character.

https://www.postgresql.org/docs/10/static/sql-copy.html

File Formats
Text Format

"
\n      Newline (ASCII 10)

Presently, COPY TO will never emit an octal or hex-digits backslash sequence, but it does use the other sequences listed above for those control characters.

...

COPY TO will terminate each row with a Unix-style newline (“\n”).
"


The second query is for the old version of PostgreSQL (9.3 and previous) cause of they don't have JSON_AGG aggregate function. Since 9.4, we have "JSON_AGG" already. So I want to rewrite and reduce the length of the query. But it is don't work as I expected with command COPY.

Thank you and best regards,


Đỗ Ngọc Trí*Cường*(Mr.) | *Software Development Department*| +84 28 3715 5325

--
Adrian Klaver
adrian.kla...@aklaver.com

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