pengzhiwei created CALCITE-2921:
-----------------------------------
Summary: nullif(null,y) throws exception in verification
Key: CALCITE-2921
URL: https://issues.apache.org/jira/browse/CALCITE-2921
Project: Calcite
Issue Type: Bug
Components: core
Affects Versions: 1.18.0
Reporter: pengzhiwei
Assignee: pengzhiwei
Currently calcite will translate "nullif(x,y)" to a case-when expression,just
like "case when x = y then null else x".So when "x" is null literal,a exception
throws out as follow:
{code:java}
ELSE clause or at least one THEN clause must be non-NULL
{code}
I have test in mysql,"nullif(null,y) works well.So I think we should allow this
usage of "nullif".
There are two ways to fix this issue:
1) Skip the check for "foundNotNull" in SqlCaseOperator#checkOperandTypes:
{code:java}
if (!foundNotNull) {
// according to the sql standard we can not have all of the THEN
// statements and the ELSE returning null
if (throwOnFailure) {
throw callBinding.newError(RESOURCE.mustNotNullInElse());
}
return false;
}{code}
However, as the comment says, we cannot have all of the THEN and ELSE returning
null.
2) Add a new SqlOperator like "NullifOperator" and disable the translation from
nullif to case-when.
Any suggestion is welcomed,Thanks!
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
