From 7e01bcfcdbc513f8a0d3266dfe64d53e3cba6d5f Mon Sep 17 00:00:00 2001
From: Tanner Clary <tannerclary@google.com>
Date: Mon, 8 Jan 2024 22:30:20 -0800
Subject: [PATCH] [CALCITE-6196] Accept BigQuery PERCENTILE functions without
 OVER clause

---
 .../calcite/rel/core/AggregateCall.java       |  5 ++--
 .../calcite/sql/fun/SqlLibraryOperators.java  |  2 --
 .../sql/validate/SqlValidatorImpl.java        |  1 -
 .../rel/rel2sql/RelToSqlConverterTest.java    | 24 +++++++++++++++++++
 4 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/core/src/main/java/org/apache/calcite/rel/core/AggregateCall.java b/core/src/main/java/org/apache/calcite/rel/core/AggregateCall.java
index fa0d978962f..bfe6b95e66c 100644
--- a/core/src/main/java/org/apache/calcite/rel/core/AggregateCall.java
+++ b/core/src/main/java/org/apache/calcite/rel/core/AggregateCall.java
@@ -467,9 +467,8 @@ public Aggregate.AggCallBinding createBinding(
     final RelDataTypeFactory typeFactory =
         aggregateRelBase.getCluster().getTypeFactory();
 
-    if (aggFunction.getKind() == SqlKind.PERCENTILE_DISC
-        || aggFunction.getKind() == SqlKind.PERCENTILE_CONT) {
-      assert collation.getKeys().size() == 1;
+    if (this.argList.size() == 1 && (aggFunction.getKind() == SqlKind.PERCENTILE_DISC
+        || aggFunction.getKind() == SqlKind.PERCENTILE_CONT)) {
       return new Aggregate.PercentileDiscAggCallBinding(typeFactory,
           aggFunction, SqlTypeUtil.projectTypes(rowType, argList),
           SqlTypeUtil.projectTypes(rowType, collation.getKeys()).get(0),
diff --git a/core/src/main/java/org/apache/calcite/sql/fun/SqlLibraryOperators.java b/core/src/main/java/org/apache/calcite/sql/fun/SqlLibraryOperators.java
index d4c8b9d1ea9..24b4c7c4b22 100644
--- a/core/src/main/java/org/apache/calcite/sql/fun/SqlLibraryOperators.java
+++ b/core/src/main/java/org/apache/calcite/sql/fun/SqlLibraryOperators.java
@@ -711,7 +711,6 @@ static RelDataType deriveTypeSplit(SqlOperatorBinding operatorBinding,
               ReturnTypes.DOUBLE,
               OperandTypes.NUMERIC_UNIT_INTERVAL_NUMERIC_LITERAL)
           .withFunctionType(SqlFunctionCategory.SYSTEM)
-          .withOver(true)
           .withPercentile(true)
           .withAllowsNullTreatment(true)
           .withAllowsFraming(false);
@@ -726,7 +725,6 @@ static RelDataType deriveTypeSplit(SqlOperatorBinding operatorBinding,
               ReturnTypes.ARG0,
               OperandTypes.NUMERIC_UNIT_INTERVAL_NUMERIC_LITERAL)
           .withFunctionType(SqlFunctionCategory.SYSTEM)
-          .withOver(true)
           .withPercentile(true)
           .withAllowsNullTreatment(true)
           .withAllowsFraming(false);
diff --git a/core/src/main/java/org/apache/calcite/sql/validate/SqlValidatorImpl.java b/core/src/main/java/org/apache/calcite/sql/validate/SqlValidatorImpl.java
index 81f2140b6a4..bf760d4f093 100644
--- a/core/src/main/java/org/apache/calcite/sql/validate/SqlValidatorImpl.java
+++ b/core/src/main/java/org/apache/calcite/sql/validate/SqlValidatorImpl.java
@@ -6235,7 +6235,6 @@ private SqlNode navigationInDefine(SqlNode node, String alpha) {
         break;
       case 2:
         assert op.allowsNullTreatment();
-        assert op.requiresOver();
         assert op.requiresGroupOrder() == Optionality.FORBIDDEN;
         break;
       default:
diff --git a/core/src/test/java/org/apache/calcite/rel/rel2sql/RelToSqlConverterTest.java b/core/src/test/java/org/apache/calcite/rel/rel2sql/RelToSqlConverterTest.java
index 7a5bc0c4993..10e08336345 100644
--- a/core/src/test/java/org/apache/calcite/rel/rel2sql/RelToSqlConverterTest.java
+++ b/core/src/test/java/org/apache/calcite/rel/rel2sql/RelToSqlConverterTest.java
@@ -1296,6 +1296,30 @@ private static String toSql(RelNode root, SqlDialect dialect,
         .withMysql().ok(expectedMysql);
   }
 
+  /** Test case for
+   * <a href="https://issues.apache.org/jira/browse/CALCITE-6196">[CALCITE-6196]
+   * Remove OVER requirement for BigQuery PERCENTILE_CONT/DISC</a>. */
+  @Test void testPercentileContFunctionWithoutOver() {
+    final String query = "select percentile_cont(\"product_id\", .5) "
+        + "from \"foodmart\".\"product\"";
+    final String expected = "SELECT PERCENTILE_CONT(product_id, 0.5)\n"
+        + "FROM foodmart.product";
+
+    sql(query).withBigQuery().withLibrary(SqlLibrary.BIG_QUERY).ok(expected);
+  }
+
+  /** Test case for
+   * <a href="https://issues.apache.org/jira/browse/CALCITE-6196">[CALCITE-6196]
+   * Remove OVER requirement for BigQuery PERCENTILE_CONT/DISC</a>. */
+  @Test void testPercentileDiscFunctionWithoutOver() {
+    final String query = "select percentile_disc(\"product_id\", .5) "
+        + "from \"foodmart\".\"product\"";
+    final String expected = "SELECT PERCENTILE_DISC(product_id, 0.5)\n"
+        + "FROM foodmart.product";
+
+    sql(query).withBigQuery().withLibrary(SqlLibrary.BIG_QUERY).ok(expected);
+  }
+
   /** As {@link #testSum0BecomesCoalesce()} but for windowed aggregates. */
   @Test void testWindowedSum0BecomesCoalesce() {
     final String query = "select\n"