initial commit

Author: sunchao

common/utils/src/main/resources/error/error-conditions.json

@@ -5714,6 +5714,18 @@
     ],
     "sqlState" : "38000"
   },
+  "QUALIFY_AGGREGATE_NOT_ALLOWED" : {
+    "message" : [
+      "Aggregate functions are not supported in QUALIFY: <aggregateExpr>."
+    ],
+    "sqlState" : "42903"
+  },
+  "QUALIFY_REQUIRES_WINDOW_FUNCTION" : {
+    "message" : [
+      "The QUALIFY clause requires at least one window function in the current SELECT list or the QUALIFY condition."
+    ],
+    "sqlState" : "42903"
+  },
   "RECURSION_LEVEL_LIMIT_EXCEEDED" : {
     "message" : [
       "Recursion level limit <levelLimit> reached but query has not exhausted, try increasing it like 'WITH RECURSIVE t(col) MAX RECURSION LEVEL 200'."

docs/sql-ref-syntax-qry-select-qualify.md

@@ -0,0 +1,98 @@
+---
+layout: global
+title: QUALIFY Clause
+displayTitle: QUALIFY Clause
+license: |
+  Licensed to the Apache Software Foundation (ASF) under one or more
+  contributor license agreements.  See the NOTICE file distributed with
+  this work for additional information regarding copyright ownership.
+  The ASF licenses this file to You under the Apache License, Version 2.0
+  (the "License"); you may not use this file except in compliance with
+  the License.  You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+---
+
+### Description
+
+The `QUALIFY` clause filters rows after window functions have been evaluated.
+It can refer to window functions in the `SELECT` list by alias, or define window
+functions directly in the `QUALIFY` condition.
+
+### Syntax
+
+```sql
+QUALIFY boolean_expression
+```
+
+### Parameters
+
+* **boolean_expression**
+
+    Specifies any expression that evaluates to a result type `boolean`. Two or
+    more expressions may be combined together using the logical
+    operators ( `AND`, `OR` ).
+
+    **Note**
+
+    The current query's `SELECT` list or the `QUALIFY` condition must contain at least
+    one window function. Aggregate functions are not allowed in the `QUALIFY` condition.
+
+### Examples
+
+```sql
+CREATE TABLE dealer (id INT, city STRING, car_model STRING, quantity INT);
+INSERT INTO dealer VALUES
+    (100, 'Fremont', 'Honda Civic', 10),
+    (100, 'Fremont', 'Honda Accord', 15),
+    (100, 'Fremont', 'Honda CRV', 7),
+    (200, 'Dublin', 'Honda Civic', 20),
+    (200, 'Dublin', 'Honda Accord', 10),
+    (200, 'Dublin', 'Honda CRV', 3),
+    (300, 'San Jose', 'Honda Civic', 5),
+    (300, 'San Jose', 'Honda Accord', 8);
+
+-- `QUALIFY` clause referring to a window function in the `SELECT` list by alias.
+SELECT city, car_model, RANK() OVER (PARTITION BY car_model ORDER BY quantity) AS rank
+FROM dealer
+QUALIFY rank = 1;
++--------+------------+----+
+|    city|   car_model|rank|
++--------+------------+----+
+|San Jose|Honda Accord|   1|
+|  Dublin|   Honda CRV|   1|
+|San Jose| Honda Civic|   1|
++--------+------------+----+
+
+-- `QUALIFY` clause with a window function directly in the predicate.
+SELECT city, car_model
+FROM dealer
+QUALIFY RANK() OVER (PARTITION BY car_model ORDER BY quantity) = 1;
++--------+------------+
+|    city|   car_model|
++--------+------------+
+|San Jose|Honda Accord|
+|  Dublin|   Honda CRV|
+|San Jose| Honda Civic|
++--------+------------+
+```
+
+### Related Statements
+
+* [SELECT Main](sql-ref-syntax-qry-select.html)
+* [WHERE Clause](sql-ref-syntax-qry-select-where.html)
+* [GROUP BY Clause](sql-ref-syntax-qry-select-groupby.html)
+* [HAVING Clause](sql-ref-syntax-qry-select-having.html)
+* [WINDOW Clause](sql-ref-syntax-qry-select-window.html)
+* [ORDER BY Clause](sql-ref-syntax-qry-select-orderby.html)
+* [SORT BY Clause](sql-ref-syntax-qry-select-sortby.html)
+* [CLUSTER BY Clause](sql-ref-syntax-qry-select-clusterby.html)
+* [DISTRIBUTE BY Clause](sql-ref-syntax-qry-select-distribute-by.html)
+* [LIMIT Clause](sql-ref-syntax-qry-select-limit.html)
+* [OFFSET Clause](sql-ref-syntax-qry-select-offset.html)

docs/sql-ref-syntax-qry-select.md

@@ -49,6 +49,8 @@ SELECT [ hints , ... ] [ ALL | DISTINCT ] { [ [ named_expression | regex_column_
     [ WHERE boolean_expression ]
     [ GROUP BY expression [ , ... ] ]
     [ HAVING boolean_expression ]
+    [ WINDOW clause ]
+    [ QUALIFY boolean_expression ]
 ```
 
 ### Parameters
@@ -122,6 +124,12 @@ SELECT [ hints , ... ] [ ALL | DISTINCT ] { [ [ named_expression | regex_column_
      filter rows after the grouping is performed. If HAVING is specified without GROUP BY, it indicates a GROUP BY
      without grouping expressions (global aggregate).
 
+* **QUALIFY**
+
+     Filters rows after window functions have been evaluated. The current `SELECT` list or the
+     `QUALIFY` condition must contain at least one window function, and aggregate functions are
+     not allowed inside the `QUALIFY` condition.
+
 * **ORDER BY**
 
      Specifies an ordering of the rows of the complete result set of the query. The output rows are ordered

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

@@ -399,6 +399,7 @@ PROCEDURE: 'PROCEDURE';
 PROCEDURES: 'PROCEDURES';
 PROPERTIES: 'PROPERTIES';
 PURGE: 'PURGE';
+QUALIFY: 'QUALIFY';
 QUARTER: 'QUARTER';
 QUERY: 'QUERY';
 RANGE: 'RANGE';

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

@@ -795,6 +795,7 @@ fromStatementBody
       aggregationClause?
       havingClause?
       windowClause?
+      qualifyClause?
       queryOrganization
     ;
 
@@ -812,7 +813,8 @@ querySpecification
       whereClause?
       aggregationClause?
       havingClause?
-      windowClause?                                                         #regularQuerySpecification
+      windowClause?
+      qualifyClause?                                                        #regularQuerySpecification
     ;
 
 transformClause
@@ -883,6 +885,10 @@ havingClause
     : HAVING booleanExpression
     ;
 
+qualifyClause
+    : QUALIFY booleanExpression
+    ;
+
 hint
     : HENT_START hintStatements+=hintStatement (COMMA? hintStatements+=hintStatement)* HENT_END
     ;
@@ -2118,6 +2124,7 @@ ansiNonReserved
     | PROCEDURES
     | PROPERTIES
     | PURGE
+    | QUALIFY
     | QUARTER
     | QUERY
     | RANGE
@@ -2530,6 +2537,7 @@ nonReserved
     | PROCEDURES
     | PROPERTIES
     | PURGE
+    | QUALIFY
     | QUARTER
     | QUERY
     | RANGE