NobiGo commented on code in PR #4403:
URL: https://github.com/apache/calcite/pull/4403#discussion_r2127725263
##########
core/src/main/java/org/apache/calcite/sql/fun/SqlInternalOperators.java:
##########
@@ -224,6 +224,40 @@ private SqlInternalOperators() {
public static final SqlAggFunction LITERAL_AGG =
SqlLiteralAggFunction.INSTANCE;
+ /** CAST NOT NULL operator used for cast expression to make it non-nullable
in SqlNode.
+ *
+ * <p>For example:
+ * <pre>{@code COALESCE(a,b)
+ * }</pre>
+ *
+ * <p>is converted to
+ *
+ * <pre>{@code CASE WHEN a is not null THEN a ELSE b
+ * }</pre>
+ * by {@code SqlCoalesceFunction#rewriteCall}.
+ *
+ * <p>When a is nullable and b is non-nullable, the {@code COALESCE(a,b)}
data type will be
+ * non-nullable and {@code CASE WHEN a is not null THEN a ELSE b} data type
will be nullable.
Review Comment:
CALCITE-3675 handles the CASE operator, there is still a difference between
COALESCE and the current PR. So I keep it.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
