zabetak commented on code in PR #4403:
URL: https://github.com/apache/calcite/pull/4403#discussion_r2123125635


##########
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:
   Can you please elaboarate a bit more on what you have in mind 
@suibianwanwank . Are you suggesting that other projects should make use of the 
new internal operator? 



##########
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:
   Can you please elaboarate a bit more on what you have in mind 
@suibianwanwank . Are you suggesting that other projects/devs should make use 
of the new internal operator? 



-- 
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]

Reply via email to