Mihai Budiu created CALCITE-6641:
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Summary: Compiling programs with ASOF joins can report obscure
errors
Key: CALCITE-6641
URL: https://issues.apache.org/jira/browse/CALCITE-6641
Project: Calcite
Issue Type: Bug
Components: core
Affects Versions: 1.38.0
Reporter: Mihai Budiu
Assignee: Mihai Budiu
A program like the following:
{code:sql}
SELECT *
FROM B
LEFT ASOF JOIN S
MATCH_CONDITION B.p_time >= S.date_time
ON B.mod = S.key
{code}
can report an error such as:
{code}
Error in SQL statement: ASOF JOIN condition must be a conjunction of equality
comparisons
ON B.mod = S.key;
^^^^^^^^^^^^^
{code}
This looks like a conjunction of equality comparisons, so the error is very
strange; internally the program represents this expression as (CAST B.mod as
BIGINT) = S.key.
This situation should be improved by either
- giving an error message that explains why the compiler does not like this
expression, or, better,
- having the ASOF join actually accept expressions that involve casts.
This is yet another problem caused by the new TypeCoercion improvements. When
the ASOF join was merged there were no casts at this point in the validation.
As was discussed briefly in [CALCITE-6639], the ASOF joins look rather brittle.
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