julianhyde commented on code in PR #3003:
URL: https://github.com/apache/calcite/pull/3003#discussion_r1066380796
##########
site/_docs/reference.md:
##########
@@ -2625,6 +2625,7 @@ semantics.
| m | EXTRACTVALUE(xml, xpathExpr)) | Returns the text of the
first text node which is a child of the element or elements matched by the
XPath expression.
| b o | GREATEST(expr [, expr ]*) | Returns the greatest of
the expressions
| b h s | IF(condition, value1, value2) | Returns *value1* if
*condition* is TRUE, *value2* otherwise
+| b | IFNULL(expr, null_result) | If expr evaluates
to NULL, returns null_result. Otherwise, returns expr. If expr doesn't evaluate
to NULL, null_result isn't evaluated.
Review Comment:
no trailing '.'
The following would be better:
```
| b | IFNULL(value1, value2) | Synonym for `NVL`
```
##########
babel/src/test/resources/sql/big-query.iq:
##########
@@ -2596,4 +2596,29 @@ FROM items;
!ok
+#####################################################################
+#
Review Comment:
move this section somewhere besides the end; add a column to distinguish the
examples
##########
testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java:
##########
@@ -6315,6 +6315,30 @@ void assertSubFunReturns(boolean binary, String s, int
start,
f12.checkNull("nvl(CAST(NULL AS VARCHAR(6)), cast(NULL AS VARCHAR(4)))");
}
+
+ @Test void testIfNullCoalesceFunc() {
Review Comment:
method should be called `testIfnullFunc`. Add comment that IFNULL is synonym
for NVL (and related to COALESCE but requires precisely two arguments)
##########
core/src/main/java/org/apache/calcite/sql/fun/SqlLibraryOperators.java:
##########
@@ -190,7 +190,10 @@ private SqlLibraryOperators() {
/** The "IFNULL(value, value)" function. */
@LibraryOperator(libraries = {BIG_QUERY})
- public static final SqlFunction IFNULL = new SqlIfNullFunction();
+ public static final SqlFunction IFNULL = SqlBasicFunction.create("IFNULL",
Review Comment:
better, `NVL.withName("IFNULL")` (you'll need to change the type of `NVL`)
##########
core/src/main/java/org/apache/calcite/sql/fun/SqlIfNullFunction.java:
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@@ -0,0 +1,73 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to you under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.calcite.sql.fun;
+
+import org.apache.calcite.sql.SqlCall;
+import org.apache.calcite.sql.SqlFunction;
+import org.apache.calcite.sql.SqlFunctionCategory;
+import org.apache.calcite.sql.SqlKind;
+import org.apache.calcite.sql.SqlNode;
+import org.apache.calcite.sql.SqlNodeList;
+import org.apache.calcite.sql.parser.SqlParserPos;
+import org.apache.calcite.sql.type.OperandTypes;
+import org.apache.calcite.sql.type.ReturnTypes;
+import org.apache.calcite.sql.type.SqlTypeTransforms;
+import org.apache.calcite.sql.validate.SqlValidator;
+import org.apache.calcite.util.Util;
+
+import java.util.List;
+
+/**
+ * The <code>IFULL</code> function.
+ */
+public class SqlIfNullFunction extends SqlFunction {
Review Comment:
Do we need this class? IFNULL is a synonym for COALESCE. (Also for NVL,
which is in the Oracle library.)
I'd make it an alias for NVL (since NVL and IFNULL have exactly 2 args).
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