Short circuit function evaluation is not applied to constant in conversion functions

[csavelief]

Hi,

First, I am using ClickHouse 21.10.5.3 according to the following query:

SELECT version()

Then, I have an inconsistent result when executing this query:

SELECT if(
  startsWith('-1671.45', '.'),
  toFloat64(concat('0', '-1671.45')),
  toFloat64('-1671.45')
)

Because

SELECT startsWith('-1671.45', '.')

returns 0, I expect the toFloat64('-1671.45') to be executed instead of toFloat64(concat('0', '-1671.45')).

Did I make a mistake somewhere?

Best,

C.

[UnamedRus]

BTW why do you need it at all?

SELECT toFloat64('.45') AS res

Query id: 5d63b722-8a4b-4bc9-941d-b2ee0fa4aa24

┌──res─┐
│ 0.45 │
└──────┘

[vdimir]

With con-constant column it works correctly (on master):

SELECT if(startsWith('-1671.45', '.'), toFloat64(materialize(concat('0', '-1671.45'))), toFloat64('-1671.45'))


┌─if(startsWith('-1671.45', '.'), toFloat64(materialize(concat('0', '-1671.45'))), toFloat64('-1671.45'))─┐
│                                                                                                -1671.45 │
└─────────────────────────────────────────────────────────────────────────────────────────────────────────┘

Ref #23367, cc @Avogar

[Avogar]

It's related to default implementation for constants in conversion functions and constant folding while query analysis. Will look is it possible to disable it for short-circuit case

[den-crane]

@csavelief

WA: toFloat64OrZero

SELECT if(startsWith('-1671.45', '.'), toFloat64OrZero(concat('0', '-1671.45')), toFloat64OrZero('-1671.45'))

Query id: 9994cec3-d8ce-4693-940b-c0de604a8675

┌─if(startsWith('-1671.45', '.'), toFloat64OrZero(concat('0', '-1671.45')), toFloat64OrZero('-1671.45'))─┐
│                                                                                               -1671.45 │
└────────────────────────────────────────────────────────────────────────────────────────────────────────┘

[csavelief]

BTW why do you need it at all?

SELECT toFloat64('.45') AS res

Query id: 5d63b722-8a4b-4bc9-941d-b2ee0fa4aa24

┌──res─┐
│ 0.45 │
└──────┘

Because it is a more complex query but I tried to report the smallest example with the issue.

WA: toFloat64OrZero

SELECT if(startsWith('-1671.45', '.'), toFloat64OrZero(concat('0', '-1671.45')), toFloat64OrZero('-1671.45'))

Query id: 9994cec3-d8ce-4693-940b-c0de604a8675

┌─if(startsWith('-1671.45', '.'), toFloat64OrZero(concat('0', '-1671.45')), toFloat64OrZero('-1671.45'))─┐
│                                                                                               -1671.45 │
└────────────────────────────────────────────────────────────────────────────────────────────────────────┘

I agree, replacing toFloat64 by toFloat64OrZero in the original query fixes the issue :-)

Thank you!

[den-crane]

constant folding

ah I see

SELECT
    materialize('-1671.45') AS x,
    if(startsWith(x, '.'), toFloat64(concat('0', x)), toFloat64(x))

Query id: 0979a0ad-83a5-49ff-af51-034efdf66317

┌─x────────┬─if(startsWith(materialize('-1671.45'), '.'), toFloat64(concat('0', materialize('-1671.45'))), toFloat64(materialize('-1671.45')))─┐
│ -1671.45 │                                                                                                                          -1671.45 │
└──────────┴───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘

[alexey-milovidov]

This is still relevant.