HIVE-27495: NPE when trying to transform using clause to on clause

ql/src/java/org/apache/hadoop/hive/ql/parse/CalcitePlanner.java

@@ -2631,6 +2631,38 @@ private RelNode genJoinRelNode(RelNode leftRel, String leftTableAlias, RelNode r
               unparseTranslator.addIdentifierTranslation((ASTNode) child);
             }
             namedColumns.add(columnName);
+
+            /*
+              In case of multiple joins, leftTableAlias can be null
+              as for the second join, the left side is a join token.
+
+              For example, if we have 3 tables with the following schemas:
+                    t1 - (a), t2 - (a, b), t3 - (a, b, c)
+              and we were trying to run the following query:
+                    select * from t1
+                    join t2 using(a)
+                    join t3 using(a);
+              For the second join, since left side is a join, leftTableAlias is null, and we have
+              to choose the correct alias to use from leftRR. Here we are choosing the rightmost
+              table containing column a, i.e., t2 and not t1.
+
+              And, for the query:
+                    select * from t2
+                    join t1 using(a)
+                    join t3 using(b);
+              For the second join, leftTableAlias is again null, and the rightmost table containing
+              column b is t2 as b is not present in t1.
+             */
+            if (leftTableAlias == null) {
+              leftTableAlias = leftRR.getTableAliasContainingColumn(columnName);
+            }
+            // if it's still null, throw an exception as column is not present
+            // in left row resolver
+            if (leftTableAlias == null) {
+              throw new SemanticException("column '" + columnName +
+                  "' not present in any of these tables: " + leftRR.getTableNames());
+            }
+
             ASTNode left = ASTBuilder.qualifiedName(leftTableAlias, columnName);
             ASTNode right = ASTBuilder.qualifiedName(rightTableAlias, columnName);
             equal = (ASTNode) ParseDriver.adaptor.create(HiveParser.EQUAL, "=");

ql/src/java/org/apache/hadoop/hive/ql/parse/RowResolver.java

@@ -309,6 +309,24 @@ public Set<String> getTableNames() {
     return rslvMap.keySet();
   }
 
+  /**
+   * Get alias of the last table containing  column columnName
+   *
+   * @param columnName column
+   * @return table alias or null
+   */
+  public String getTableAliasContainingColumn(String columnName) {
+    String result = null;
+
+    for (Map.Entry<String, Map<String, ColumnInfo>> entry: this.rslvMap.entrySet()) {
+      if (entry.getValue().containsKey(columnName)) {
+        result = entry.getKey();
+      }
+    }
+
+    return result;
+  }
+
   public String[] reverseLookup(String internalName) {
     return invRslvMap.get(internalName);
   }

ql/src/test/queries/clientnegative/join_using_clause_ambiguous_table.q

@@ -0,0 +1,7 @@
+create table test(
+    a int
+);
+
+select * from test
+join test using(a)
+join test using(a);

ql/src/test/queries/clientnegative/join_using_clause_wrong_column.q

@@ -0,0 +1,8 @@
+
+create table test(
+    a int
+);
+
+select * from test t1
+join test t2 using(a)
+join test t3 using(b);

ql/src/test/queries/clientpositive/join_using_clause.q

@@ -0,0 +1,77 @@
+
+create table test (
+ a int
+);
+
+insert into test values (1);
+
+create table test1 (
+ a int,
+ b int
+);
+
+insert into test1 values (1, 2);
+
+create table test2 (
+ a int,
+ b int,
+ c int
+);
+
+insert into test2 values (1, 2, 3);
+
+-- self join with 1 column
+select * from test t1
+join test t2 using(a)
+join test t3 using(a);
+
+explain cbo select * from test t1
+join test t2 using(a)
+join test t3 using(a);
+
+-- self join with multiple columns
+select * from test1 t1
+join test1 t2 using(a)
+join test1 t3 using(b);
+
+explain cbo select * from test1 t1
+join test1 t2 using(a)
+join test1 t3 using(b);
+
+-- joins with multiple tables and columns
+select * from test1 t1
+join test t2 using(a)
+join test2 t3 using(b);
+
+explain cbo select * from test1 t1
+join test t2 using(a)
+join test2 t3 using(b);
+
+select * from test t1
+join test1 t2 using(a)
+join test2 t3 using(b)
+join test2 t4 using(c);
+
+explain cbo select * from test t1
+join test1 t2 using(a)
+join test2 t3 using(b)
+join test2 t4 using(c);
+
+select * from test1 t1
+join test2 t2 using(a, b)
+join test2 t3 using(c, b)
+join test t4 using(a);
+
+explain cbo select * from test1 t1
+join test2 t2 using(a, b)
+join test2 t3 using(c, b)
+join test t4 using(a);
+
+-- joins without table alias
+select * from test1
+join test using(a)
+join test2 using(b);
+
+explain cbo select * from test1
+join test using(a)
+join test2 using(b);

ql/src/test/results/clientnegative/join_using_clause_ambiguous_table.q.out

@@ -0,0 +1,13 @@
+PREHOOK: query: create table test(
+    a int
+)
+PREHOOK: type: CREATETABLE
+PREHOOK: Output: database:default
+PREHOOK: Output: default@test
+POSTHOOK: query: create table test(
+    a int
+)
+POSTHOOK: type: CREATETABLE
+POSTHOOK: Output: database:default
+POSTHOOK: Output: default@test
+FAILED: SemanticException [Error 10008]: Line 4:5 Ambiguous table alias 'test'

ql/src/test/results/clientnegative/join_using_clause_wrong_column.q.out

@@ -0,0 +1,13 @@
+PREHOOK: query: create table test(
+    a int
+)
+PREHOOK: type: CREATETABLE
+PREHOOK: Output: database:default
+PREHOOK: Output: default@test
+POSTHOOK: query: create table test(
+    a int
+)
+POSTHOOK: type: CREATETABLE
+POSTHOOK: Output: database:default
+POSTHOOK: Output: default@test
+FAILED: SemanticException column 'b' not present in any of these tables: [t1, t2]