SQL: Fix assumption that AND, OR have two arguments.

sql/src/main/java/io/druid/sql/calcite/expression/BinaryOperatorConversion.java

@@ -19,22 +19,25 @@
 
 package io.druid.sql.calcite.expression;
 
+import com.google.common.base.Joiner;
 import io.druid.java.util.common.ISE;
 import io.druid.java.util.common.StringUtils;
 import io.druid.sql.calcite.planner.PlannerContext;
 import io.druid.sql.calcite.table.RowSignature;
 import org.apache.calcite.rex.RexNode;
 import org.apache.calcite.sql.SqlOperator;
 
+import java.util.stream.Collectors;
+
 public class BinaryOperatorConversion implements SqlOperatorConversion
 {
   private final SqlOperator operator;
-  private final String druidOperator;
+  private final Joiner joiner;
 
   public BinaryOperatorConversion(final SqlOperator operator, final String druidOperator)
   {
     this.operator = operator;
-    this.druidOperator = druidOperator;
+    this.joiner = Joiner.on(" " + druidOperator + " ");
   }
 
   @Override
@@ -55,16 +58,18 @@ public DruidExpression toDruidExpression(
         rowSignature,
         rexNode,
         operands -> {
-          if (operands.size() != 2) {
+          if (operands.size() < 2) {
             throw new ISE("WTF?! Got binary operator[%s] with %s args?", operator.getName(), operands.size());
           }
 
           return DruidExpression.fromExpression(
               StringUtils.format(
-                  "(%s %s %s)",
-                  operands.get(0).getExpression(),
-                  druidOperator,
-                  operands.get(1).getExpression()
+                  "(%s)",
+                  joiner.join(
+                      operands.stream()
+                              .map(DruidExpression::getExpression)
+                              .collect(Collectors.toList())
+                  )
               )
           );
         }

sql/src/test/java/io/druid/sql/calcite/CalciteQueryTest.java

@@ -1597,6 +1597,39 @@ public void testGroupByCaseWhen() throws Exception
     );
   }
 
+  @Test
+  public void testGroupByCaseWhenOfTripleAnd() throws Exception
+  {
+    testQuery(
+        "SELECT\n"
+        + "  CASE WHEN m1 > 1 AND m1 < 5 AND cnt = 1 THEN 'x' ELSE NULL END,"
+        + "  COUNT(*)\n"
+        + "FROM druid.foo\n"
+        + "GROUP BY 1",
+        ImmutableList.of(
+            GroupByQuery.builder()
+                        .setDataSource(CalciteTests.DATASOURCE1)
+                        .setInterval(QSS(Filtration.eternity()))
+                        .setGranularity(Granularities.ALL)
+                        .setVirtualColumns(
+                            EXPRESSION_VIRTUAL_COLUMN(
+                                "d0:v",
+                                "case_searched(((\"m1\" > 1) && (\"m1\" < 5) && (\"cnt\" == 1)),'x','')",
+                                ValueType.STRING
+                            )
+                        )
+                        .setDimensions(DIMS(new DefaultDimensionSpec("d0:v", "d0")))
+                        .setAggregatorSpecs(AGGS(new CountAggregatorFactory("a0")))
+                        .setContext(QUERY_CONTEXT_DEFAULT)
+                        .build()
+        ),
+        ImmutableList.of(
+            new Object[]{"", 3L},
+            new Object[]{"x", 3L}
+        )
+    );
+  }
+
   @Test
   public void testNullEmptyStringEquality() throws Exception
   {