ILuffZhe commented on code in PR #4462:
URL: https://github.com/apache/calcite/pull/4462#discussion_r2194740220
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core/src/main/java/org/apache/calcite/sql2rel/StandardConvertletTable.java:
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@@ -1952,10 +1960,32 @@ private static class TrimConvertlet implements
SqlRexConvertlet {
@Override public RexNode convertCall(SqlRexContext cx, SqlCall call) {
final RexBuilder rexBuilder = cx.getRexBuilder();
+ final SqlParserPos pos = call.getParserPosition();
+ final RelDataTypeFactory typeFactory =
+ cx.getValidator().getTypeFactory();
final RexNode operand =
cx.convertExpression(call.getOperandList().get(0));
- return rexBuilder.makeCall(call.getParserPosition(),
SqlStdOperatorTable.TRIM,
- rexBuilder.makeFlag(flag), rexBuilder.makeLiteral(" "), operand);
+ RexNode rawCall =
+ rexBuilder.makeCall(pos, SqlStdOperatorTable.TRIM,
rexBuilder.makeFlag(flag),
+ rexBuilder.makeLiteral(" "), operand);
+ SqlConformance conformance = cx.getValidator().config().conformance();
+ if (conformance.emptyStringIsNull()) {
+ // Translate
+ // LTRIM/RTRIM(operand0[,operand1,...])
+ //
+ // to the following if we want Oracle semantics
Review Comment:
> Here, we convert LTRIM(A) to the following expression: CASE WHEN LTRIM(A)
= '' THEN NULL ELSE LTRIM(A) END. LTRIM(A) is calculated multiple times. If
LTRIM(A) is a non-deterministic function, it may lead to an uncontrolled final
result.
Nondeterministic is not allowed during runtime, I've added some tests and
throw exception when it occurs.
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