[SPARK-20690][SQL] Subqueries in FROM should have alias names

sql/catalyst/src/main/antlr4/org/apache/spark/sql/catalyst/parser/SqlBase.g4

@@ -473,7 +473,7 @@ identifierComment
 
 relationPrimary
     : tableIdentifier sample? (AS? strictIdentifier)?      #tableName
-    | '(' queryNoWith ')' sample? (AS? strictIdentifier)?  #aliasedQuery
+    | '(' queryNoWith ')' sample? (AS? strictIdentifier)   #aliasedQuery
     | '(' relation ')' sample? (AS? strictIdentifier)?     #aliasedRelation
     | inlineTable                                          #inlineTableDefault2
     | functionTable                                        #tableValuedFunction

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala

@@ -1045,7 +1045,7 @@ class Analyzer(
       // Skip sort with aggregate. This will be handled in ResolveAggregateFunctions
       case sa @ Sort(_, _, child: Aggregate) => sa
 
-      case s @ Sort(order, _, child) if child.resolved =>
+      case s @ Sort(order, _, child) if !s.resolved && child.resolved =>
         try {
           val newOrder = order.map(resolveExpressionRecursively(_, child).asInstanceOf[SortOrder])
           val requiredAttrs = AttributeSet(newOrder).filter(_.resolved)
@@ -1066,7 +1066,7 @@ class Analyzer(
           case ae: AnalysisException => s
         }
 
-      case f @ Filter(cond, child) if child.resolved =>
+      case f @ Filter(cond, child) if !f.resolved && child.resolved =>
         try {
           val newCond = resolveExpressionRecursively(cond, child)
           val requiredAttrs = newCond.references.filter(_.resolved)

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/parser/AstBuilder.scala

@@ -745,9 +745,8 @@ class AstBuilder(conf: SQLConf) extends SqlBaseBaseVisitor[AnyRef] with Logging
    * hooks.
    */
   override def visitAliasedQuery(ctx: AliasedQueryContext): LogicalPlan = withOrigin(ctx) {
-    plan(ctx.queryNoWith)
-      .optionalMap(ctx.sample)(withSample)
-      .optionalMap(ctx.strictIdentifier)(aliasPlan)
+    aliasPlan(ctx.strictIdentifier,
+      plan(ctx.queryNoWith).optionalMap(ctx.sample)(withSample))
   }
 
   /**

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/basicLogicalOperators.scala

@@ -798,6 +798,12 @@ case class LocalLimit(limitExpr: Expression, child: LogicalPlan) extends UnaryNo
   }
 }
 
+/**
+ * Aliased subquery.
+ *
+ * @param alias the alias name for this subquery.
+ * @param child the logical plan of this subquery.
+ */
 case class SubqueryAlias(
     alias: String,
     child: LogicalPlan)

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/parser/PlanParserSuite.scala

@@ -444,6 +444,17 @@ class PlanParserSuite extends PlanTest {
         |      (select id from t0)) as u_1
       """.stripMargin,
       plan.union(plan).union(plan).as("u_1").select('id))
+
+  }
+
+  test("aliased subquery") {
+    assertEqual("select a from (select id as a from t0) tt",
+      table("t0").select('id.as("a")).as("tt").select('a))
+    intercept("select a from (select id as a from t0)", "mismatched input")
+
+    assertEqual("from (select id as a from t0) tt select a",
+      table("t0").select('id.as("a")).as("tt").select('a))
+    intercept("from (select id as a from t0) select a", "extraneous input 'a'")
   }
 
   test("scalar sub-query") {

sql/core/src/test/resources/sql-tests/inputs/group-by.sql

@@ -34,7 +34,7 @@ SELECT SKEWNESS(a), KURTOSIS(a), MIN(a), MAX(a), AVG(a), VARIANCE(a), STDDEV(a),
 FROM testData;
 
 -- Aggregate with foldable input and multiple distinct groups.
-SELECT COUNT(DISTINCT b), COUNT(DISTINCT b, c) FROM (SELECT 1 AS a, 2 AS b, 3 AS c) GROUP BY a;
+SELECT COUNT(DISTINCT b), COUNT(DISTINCT b, c) FROM (SELECT 1 AS a, 2 AS b, 3 AS c) t GROUP BY a;
 
 -- Aliases in SELECT could be used in GROUP BY
 SELECT a AS k, COUNT(b) FROM testData GROUP BY k;

sql/core/src/test/resources/sql-tests/inputs/limit.sql

@@ -21,7 +21,7 @@ SELECT * FROM testdata LIMIT true;
 SELECT * FROM testdata LIMIT 'a';
 
 -- limit within a subquery
-SELECT * FROM (SELECT * FROM range(10) LIMIT 5) WHERE id > 3;
+SELECT * FROM (SELECT * FROM range(10) LIMIT 5) t WHERE id > 3;
 
 -- limit ALL
 SELECT * FROM testdata WHERE key < 3 LIMIT ALL;

sql/core/src/test/resources/sql-tests/inputs/string-functions.sql

@@ -7,4 +7,4 @@ select 'a' || 'b' || 'c';
 
 -- Check if catalyst combine nested `Concat`s
 EXPLAIN EXTENDED SELECT (col1 || col2 || col3 || col4) col
-FROM (SELECT id col1, id col2, id col3, id col4 FROM range(10));
+FROM (SELECT id col1, id col2, id col3, id col4 FROM range(10)) t;

sql/core/src/test/resources/sql-tests/inputs/subquery/in-subquery/in-set-operations.sql

@@ -394,7 +394,7 @@ FROM   (SELECT *
                              FROM   t1)) t4
         WHERE  t4.t2b IN (SELECT Min(t3b)
                           FROM   t3
-                          WHERE  t4.t2a = t3a));
+                          WHERE  t4.t2a = t3a)) T;
 
 -- UNION, UNION ALL, UNION DISTINCT, INTERSECT and EXCEPT for NOT IN
 -- TC 01.12

sql/core/src/test/resources/sql-tests/inputs/subquery/negative-cases/invalid-correlation.sql

@@ -23,7 +23,7 @@ AND    t2b = (SELECT max(avg)
               FROM   (SELECT   t2b, avg(t2b) avg
                       FROM     t2
                       WHERE    t2a = t1.t1b
-                     )
+                     ) T
              )
 ;
 

sql/core/src/test/resources/sql-tests/inputs/subquery/scalar-subquery/scalar-subquery-predicate.sql

@@ -19,7 +19,7 @@ AND    c.cv = (SELECT max(avg)
                FROM   (SELECT   c1.cv, avg(c1.cv) avg
                        FROM     c c1
                        WHERE    c1.ck = p.pk
-                       GROUP BY c1.cv));
+                       GROUP BY c1.cv) T);
 
 create temporary view t1 as select * from values
   ('val1a', 6S, 8, 10L, float(15.0), 20D, 20E2, timestamp '2014-04-04 00:00:00.000', date '2014-04-04'),

sql/core/src/test/resources/sql-tests/inputs/union.sql

@@ -5,15 +5,15 @@ CREATE OR REPLACE TEMPORARY VIEW t2 AS VALUES (1.0, 1), (2.0, 4) tbl(c1, c2);
 SELECT *
 FROM   (SELECT * FROM t1
         UNION ALL
-        SELECT * FROM t1);
+        SELECT * FROM t1) T;
 
 -- Type Coerced Union
 SELECT *
 FROM   (SELECT * FROM t1
         UNION ALL
         SELECT * FROM t2
         UNION ALL
-        SELECT * FROM t2);
+        SELECT * FROM t2) T;
 
 -- Regression test for SPARK-18622
 SELECT a

sql/core/src/test/resources/sql-tests/results/group-by.sql.out

@@ -134,7 +134,7 @@ struct<skewness(CAST(a AS DOUBLE)):double,kurtosis(CAST(a AS DOUBLE)):double,min
 
 
 -- !query 14
-SELECT COUNT(DISTINCT b), COUNT(DISTINCT b, c) FROM (SELECT 1 AS a, 2 AS b, 3 AS c) GROUP BY a
+SELECT COUNT(DISTINCT b), COUNT(DISTINCT b, c) FROM (SELECT 1 AS a, 2 AS b, 3 AS c) t GROUP BY a
 -- !query 14 schema
 struct<count(DISTINCT b):bigint,count(DISTINCT b, c):bigint>
 -- !query 14 output

sql/core/src/test/resources/sql-tests/results/limit.sql.out

@@ -93,7 +93,7 @@ The limit expression must be integer type, but got string;
 
 
 -- !query 10
-SELECT * FROM (SELECT * FROM range(10) LIMIT 5) WHERE id > 3
+SELECT * FROM (SELECT * FROM range(10) LIMIT 5) t WHERE id > 3
 -- !query 10 schema
 struct<id:bigint>
 -- !query 10 output

sql/core/src/test/resources/sql-tests/results/string-functions.sql.out

@@ -30,20 +30,22 @@ abc
 
 -- !query 3
 EXPLAIN EXTENDED SELECT (col1 || col2 || col3 || col4) col
-FROM (SELECT id col1, id col2, id col3, id col4 FROM range(10))
+FROM (SELECT id col1, id col2, id col3, id col4 FROM range(10)) t
 -- !query 3 schema
 struct<plan:string>
 -- !query 3 output
 == Parsed Logical Plan ==
 'Project [concat(concat(concat('col1, 'col2), 'col3), 'col4) AS col#x]
-+- 'Project ['id AS col1#x, 'id AS col2#x, 'id AS col3#x, 'id AS col4#x]
-   +- 'UnresolvedTableValuedFunction range, [10]
++- 'SubqueryAlias t
+   +- 'Project ['id AS col1#x, 'id AS col2#x, 'id AS col3#x, 'id AS col4#x]
+      +- 'UnresolvedTableValuedFunction range, [10]
 
 == Analyzed Logical Plan ==
 col: string
 Project [concat(concat(concat(cast(col1#xL as string), cast(col2#xL as string)), cast(col3#xL as string)), cast(col4#xL as string)) AS col#x]
-+- Project [id#xL AS col1#xL, id#xL AS col2#xL, id#xL AS col3#xL, id#xL AS col4#xL]
-   +- Range (0, 10, step=1, splits=None)
++- SubqueryAlias t
+   +- Project [id#xL AS col1#xL, id#xL AS col2#xL, id#xL AS col3#xL, id#xL AS col4#xL]
+      +- Range (0, 10, step=1, splits=None)
 
 == Optimized Logical Plan ==
 Project [concat(cast(id#xL as string), cast(id#xL as string), cast(id#xL as string), cast(id#xL as string)) AS col#x]

sql/core/src/test/resources/sql-tests/results/subquery/in-subquery/in-set-operations.sql.out

@@ -496,7 +496,7 @@ FROM   (SELECT *
                              FROM   t1)) t4
         WHERE  t4.t2b IN (SELECT Min(t3b)
                           FROM   t3
-                          WHERE  t4.t2a = t3a))
+                          WHERE  t4.t2a = t3a)) T
 -- !query 13 schema
 struct<t2a:string,t2b:smallint,t2c:int,t2d:bigint,t2e:float,t2f:double,t2g:decimal(2,-2),t2h:timestamp,t2i:date>
 -- !query 13 output

sql/core/src/test/resources/sql-tests/results/subquery/negative-cases/invalid-correlation.sql.out

@@ -40,7 +40,7 @@ AND    t2b = (SELECT max(avg)
               FROM   (SELECT   t2b, avg(t2b) avg
                       FROM     t2
                       WHERE    t2a = t1.t1b
-                     )
+                     ) T
              )
 -- !query 3 schema
 struct<>

sql/core/src/test/resources/sql-tests/results/subquery/scalar-subquery/scalar-subquery-predicate.sql.out

@@ -39,7 +39,7 @@ AND    c.cv = (SELECT max(avg)
                FROM   (SELECT   c1.cv, avg(c1.cv) avg
                        FROM     c c1
                        WHERE    c1.ck = p.pk
-                       GROUP BY c1.cv))
+                       GROUP BY c1.cv) T)
 -- !query 3 schema
 struct<pk:int,cv:int>
 -- !query 3 output

sql/core/src/test/resources/sql-tests/results/union.sql.out

@@ -22,7 +22,7 @@ struct<>
 SELECT *
 FROM   (SELECT * FROM t1
         UNION ALL
-        SELECT * FROM t1)
+        SELECT * FROM t1) T
 -- !query 2 schema
 struct<c1:int,c2:string>
 -- !query 2 output
@@ -38,7 +38,7 @@ FROM   (SELECT * FROM t1
         UNION ALL
         SELECT * FROM t2
         UNION ALL
-        SELECT * FROM t2)
+        SELECT * FROM t2) T
 -- !query 3 schema
 struct<c1:decimal(11,1),c2:string>
 -- !query 3 output

sql/core/src/test/scala/org/apache/spark/sql/CachedTableSuite.scala

@@ -631,13 +631,13 @@ class CachedTableSuite extends QueryTest with SQLTestUtils with SharedSQLContext
       val ds2 =
         sql(
           """
-            |SELECT * FROM (SELECT max(c1) FROM t1 GROUP BY c1)
+            |SELECT * FROM (SELECT max(c1) as c1 FROM t1 GROUP BY c1) tt
             |WHERE
-            |c1 = (SELECT max(c1) FROM t2 GROUP BY c1)
+            |tt.c1 = (SELECT max(c1) FROM t2 GROUP BY c1)
             |OR
             |EXISTS (SELECT c1 FROM t3)
             |OR
-            |c1 IN (SELECT c1 FROM t4)
+            |tt.c1 IN (SELECT c1 FROM t4)
           """.stripMargin)
       assert(getNumInMemoryRelations(ds2) == 4)
     }
@@ -788,25 +788,25 @@ class CachedTableSuite extends QueryTest with SQLTestUtils with SharedSQLContext
       // Scalar subquery and predicate subquery
       sql(
         """
-          |SELECT * FROM (SELECT max(c1) FROM t1 GROUP BY c1)
+          |SELECT * FROM (SELECT max(c1) as c1 FROM t1 GROUP BY c1) tt
           |WHERE
-          |c1 = (SELECT max(c1) FROM t2 GROUP BY c1)
+          |tt.c1 = (SELECT max(c1) FROM t2 GROUP BY c1)
           |OR
           |EXISTS (SELECT c1 FROM t3)
           |OR
-          |c1 IN (SELECT c1 FROM t4)
+          |tt.c1 IN (SELECT c1 FROM t4)
         """.stripMargin).cache()
 
       val cachedDs2 =
         sql(
           """
-            |SELECT * FROM (SELECT max(c1) FROM t1 GROUP BY c1)
+            |SELECT * FROM (SELECT max(c1) as c1 FROM t1 GROUP BY c1) tt
             |WHERE
-            |c1 = (SELECT max(c1) FROM t2 GROUP BY c1)
+            |tt.c1 = (SELECT max(c1) FROM t2 GROUP BY c1)
             |OR
             |EXISTS (SELECT c1 FROM t3)
             |OR
-            |c1 IN (SELECT c1 FROM t4)
+            |tt.c1 IN (SELECT c1 FROM t4)
           """.stripMargin)
       assert(getNumInMemoryRelations(cachedDs2) == 1)
     }

sql/core/src/test/scala/org/apache/spark/sql/SubquerySuite.scala

@@ -112,7 +112,7 @@ class SubquerySuite extends QueryTest with SharedSQLContext {
           |   with t4 as (select 1 as d, 3 as e)
           |   select * from t4 cross join t2 where t2.b = t4.d
           | )
-          | select a from (select 1 as a union all select 2 as a)
+          | select a from (select 1 as a union all select 2 as a) t
           | where a = (select max(d) from t3)
         """.stripMargin),
       Array(Row(1))
@@ -606,8 +606,8 @@ class SubquerySuite extends QueryTest with SharedSQLContext {
             |    select cntPlusOne + 1 as cntPlusTwo from (
             |        select cnt + 1 as cntPlusOne from (
             |            select sum(r.c) s, count(*) cnt from r where l.a = r.c having cnt = 0
-            |        )
-            |    )
+            |        ) t1
+            |    ) t2
             |) = 2""".stripMargin),
       Row(1) :: Row(1) :: Row(null) :: Row(null) :: Nil)
   }
@@ -655,7 +655,7 @@ class SubquerySuite extends QueryTest with SharedSQLContext {
           """
             | select c1 from onerow t1
             | where exists (select 1
-            |               from   (select 1 from onerow t2 LIMIT 1)
+            |               from   (select 1 as c1 from onerow t2 LIMIT 1) t2
             |               where  t1.c1=t2.c1)""".stripMargin),
         Row(1) :: Nil)
     }