[Tarantool-discussions] Implicit cast for ASSIGNMENT

Peter Gulutzan pgulutzan at ocelot.ca
Thu Apr 30 17:15:52 MSK 2020


On 2020-04-30 8:04 a.m., Konstantin Osipov wrote:
 > * Imeev Mergen <imeevma at tarantool.org> [20/04/30 16:14]:
 >> On 4/30/20 4:09 PM, Konstantin Osipov wrote:
 >>> * Imeev Mergen <imeevma at tarantool.org> [20/04/30 15:59]:
 >>>>> The only possible exception is conversion of a lossless conversion
 >>>>> of a numeric literal, e.g.:
 >>>>> float_val = 1.1 -- implicitly convert decimal constant 1.1 to float
 >>>> So, is it fine to implicitly cast 1.0(DOUBLE) to 1(INTEGER)?
 >>> 1.0 is not double, it's DECIMAL.
 >> Ok, then, let's say we executed something like this:
 >> box.execute('CREATE TABLE t (i INT PRIMARY KEY);')
 >> box.execute('INSERT INTO t VALUES(CAST(1 AS DOUBLE));')
 >> Should this work of we should receive an error?
 > I think it shouldn't because CAST(1 AS DOUBLE) is an expression,
 > not a constant literal.

I of course think that it should work,
but K. Yukhin decided it should not work.

With regard to the earlier questions

Unfortunately assigning 1.1 to an INTEGER fails.
"Implicit casting among the numeric data types"
is a mandatory feature of standard SQL,
My opinion was that implicit cast should be legal
However, K. Yukhin closed that issue.

I also believed that typeof(1.0) should be DECIMAL.
But currently typeof(1.0) is DOUBLE.

Peter Gulutzan

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