Revert "[CALCITE-6978] Translation to relational algebra of correlated query with COALESCE causes an assertion failure"

This reverts commit 60e1b72.

Reverting as CALCITE-7035 highlighted issues for missing rewrites of calls without implementors/converlet

This issue will be addressed by CALCITE-7012

Author: asolimando

core/src/main/java/org/apache/calcite/sql/validate/SqlValidatorImpl.java

@@ -1528,9 +1528,7 @@ private void handleOffsetFetch(@Nullable SqlNode offset, @Nullable SqlNode fetch
           ((SqlBasicCall) call).setOperator(overloads.get(0));
         }
       }
-      if (config.callRewrite()
-          // Do not rewrite calls that contain subqueries
-          && !SqlUtil.containsCall(call, c -> c.getKind() == SqlKind.SELECT)) {
+      if (config.callRewrite()) {
         node = call.getOperator().rewriteCall(this, call);
       }
     } else if (node instanceof SqlNodeList) {

core/src/test/java/org/apache/calcite/test/SqlToRelConverterTest.java

@@ -1678,18 +1678,6 @@ public static void checkActualAndReferenceFiles() {
     sql(sql).ok();
   }
 
-  /** Test case for <a href="https://issues.apache.org/jira/browse/CALCITE-6978">[CALCITE-6978]
-   * Translation to relational algebra of correlated query with COALESCE causes an
-   * assertion failure</a>. */
-  @Test void testCoalesceSubquery() {
-    final String sql = "SELECT"
-        + "  deptno, "
-        + "  coalesce((select sum(empno) from emp "
-        + "  where deptno = emp.deptno limit 1), 0) as w "
-        + "FROM dept";
-    sql(sql).ok();
-  }
-
   @Test void testSampleBernoulliQuery() {
     final String sql = "select * from (\n"
         + " select * from emp as e tablesample bernoulli(10) repeatable(1)\n"

core/src/test/resources/org/apache/calcite/test/SqlToRelConverterTest.xml

@@ -651,23 +651,6 @@ LogicalProject(EXPR$0=[CHAR_LENGTH('foo')])
       <![CDATA[
 LogicalProject(EXPR$0=[CASE(IS NOT NULL($3), CAST($3):INTEGER NOT NULL, 0)])
   LogicalTableScan(table=[[CATALOG, SALES, EMP]])
-]]>
-    </Resource>
-  </TestCase>
-  <TestCase name="testCoalesceSubquery">
-    <Resource name="sql">
-      <![CDATA[SELECT  deptno,   coalesce((select sum(empno) from emp   where deptno = emp.deptno limit 1), 0) as w FROM dept]]>
-    </Resource>
-    <Resource name="plan">
-      <![CDATA[
-LogicalProject(DEPTNO=[$0], W=[COALESCE($2, 0)])
-  LogicalJoin(condition=[true], joinType=[left])
-    LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
-    LogicalSort(fetch=[1])
-      LogicalAggregate(group=[{}], EXPR$0=[SUM($0)])
-        LogicalProject(EMPNO=[$0])
-          LogicalFilter(condition=[=($7, $7)])
-            LogicalTableScan(table=[[CATALOG, SALES, EMP]])
 ]]>
     </Resource>
   </TestCase>

core/src/test/resources/sql/sub-query.iq

@@ -1134,7 +1134,7 @@ EnumerableCalc(expr#0..3=[{inputs}], ENAME=[$t1], DEEP2SAL=[$t3])
       EnumerableTableScan(table=[[scott, EMP]])
     EnumerableSort(sort0=[$0], dir0=[ASC])
       EnumerableAggregate(group=[{0}], EXPR$0=[SUM($1)])
-        EnumerableCalc(expr#0..4=[{inputs}], expr#5=[0], expr#6=[COALESCE($t4, $t5)], expr#7=[+($t2, $t6)], MGR9=[$t1], $f0=[$t7])
+        EnumerableCalc(expr#0..4=[{inputs}], expr#5=[IS NOT NULL($t4)], expr#6=[0.00:DECIMAL(19, 2)], expr#7=[CASE($t5, $t4, $t6)], expr#8=[+($t2, $t7)], MGR9=[$t1], $f0=[$t8])
           EnumerableMergeJoin(condition=[=($0, $3)], joinType=[left])
             EnumerableCalc(expr#0..7=[{inputs}], expr#8=[IS NOT NULL($t3)], EMPNO=[$t0], MGR=[$t3], SAL=[$t5], $condition=[$t8])
               EnumerableTableScan(table=[[scott, EMP]])