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Message-ID: <9dc702ca-8bb3-442e-bd2b-12abe81a84d0@aklaver.com>
Date: Sat, 10 Aug 2024 07:52:31 -0700
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Subject: Re: Insert works but fails for merge
To: yudhi s <learnerdatabase99@gmail.com>,
 "David G. Johnston" <david.g.johnston@gmail.com>
Cc: pgsql-general <pgsql-general@lists.postgresql.org>
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From: Adrian Klaver <adrian.klaver@aklaver.com>
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On 8/10/24 05:07, yudhi s wrote:
> 
> 

> Thank You Adrian and David.
> 
> Even converting the merge avoiding the WITH clause/CTE as below , is 
> still making it fail with the same error. So it seems , only 
> direct "insert into values" query can be auto converted/casted but not 
> the other queries.
> 
> In our case , we were using this merge query in application code(in 
> Java) as a framework to dynamically take these values as bind values and 
> do the merge of input data/message. But it seems we have to now cast 
> each and every field which we get from the incoming message to make 
> this merge work in a correct way. I am wondering if the only way now is 
> to get the data types from information_schema.columns and then use the 
> cast function to write the values of the merge query dynamically 
> casted/converted for each of the fields in the application code. Please 
> correct me if my understanding is wrong.

Why not use INSERT ... ON CONFLICT instead of MERGE?

> 
> MERGE INTO tab1 AS target
> USING (VALUES ('5efd4c91-ef93-4477-840c-a723ae212d99', 123, 
> '2024-08-09T11:33:49.402585600Z','2024-08-09T11:33:49.402585600Z')) AS 
> source(id, mid,txn_timestamp, cre_ts)
> ON target.id <http://target.id> = source.id <http://source.id>
> WHEN MATCHED THEN
> UPDATE SET mid  = source.mid
> WHEN NOT MATCHED THEN
> INSERT (id, mid, txn_timestamp, cre_ts)
>      VALUES (source.id <http://source.id>,source.mid, 
>   source.txn_timestamp, source.cre_ts);

-- 
Adrian Klaver
adrian.klaver@aklaver.com