spark-instrumented-optimizer/docs/sql-ref-syntax-qry-select-having.md
GuoPhilipse 8de43338be [SPARK-31753][SQL][DOCS] Add missing keywords in the SQL docs
### What changes were proposed in this pull request?
update sql-ref docs, the following key words will be added in this PR.

CASE/ELSE
WHEN/THEN
MAP KEYS TERMINATED BY
NULL DEFINED AS
LINES TERMINATED BY
ESCAPED BY
COLLECTION ITEMS TERMINATED BY
PIVOT
LATERAL VIEW OUTER?
ROW FORMAT SERDE
ROW FORMAT DELIMITED
FIELDS TERMINATED BY
IGNORE NULLS
FIRST
LAST

### Why are the changes needed?
let more users know the sql key words usage

### Does this PR introduce _any_ user-facing change?
![image](https://user-images.githubusercontent.com/46367746/88148830-c6dc1f80-cc31-11ea-81ea-13bc9dc34550.png)
![image](https://user-images.githubusercontent.com/46367746/88148968-fb4fdb80-cc31-11ea-8649-e8297cf5813e.png)
![image](https://user-images.githubusercontent.com/46367746/88149000-073b9d80-cc32-11ea-9aa4-f914ecd72663.png)
![image](https://user-images.githubusercontent.com/46367746/88149021-0f93d880-cc32-11ea-86ed-7db8672b5aac.png)

### How was this patch tested?
No

Closes #29056 from GuoPhilipse/add-missing-keywords.

Lead-authored-by: GuoPhilipse <guofei_ok@126.com>
Co-authored-by: GuoPhilipse <46367746+GuoPhilipse@users.noreply.github.com>
Signed-off-by: Takeshi Yamamuro <yamamuro@apache.org>
2020-07-28 09:41:53 +09:00

3.9 KiB

layout title displayTitle license
global HAVING Clause HAVING Clause 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 HAVING clause is used to filter the results produced by GROUP BY based on the specified condition. It is often used in conjunction with a GROUP BY clause.

Syntax

HAVING 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 expressions specified in the HAVING clause can only refer to:

    1. Constants
    2. Expressions that appear in GROUP BY
    3. Aggregate functions

Examples

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);

-- `HAVING` clause referring to column in `GROUP BY`.
SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING city = 'Fremont';
+-------+---+
|   city|sum|
+-------+---+
|Fremont| 32|
+-------+---+

-- `HAVING` clause referring to aggregate function.
SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING sum(quantity) > 15;
+-------+---+
|   city|sum|
+-------+---+
| Dublin| 33|
|Fremont| 32|
+-------+---+

-- `HAVING` clause referring to aggregate function by its alias.
SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING sum > 15;
+-------+---+
|   city|sum|
+-------+---+
| Dublin| 33|
|Fremont| 32|
+-------+---+

-- `HAVING` clause referring to a different aggregate function than what is present in
-- `SELECT` list.
SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING max(quantity) > 15;
+------+---+
|  city|sum|
+------+---+
|Dublin| 33|
+------+---+

-- `HAVING` clause referring to constant expression.
SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING 1 > 0 ORDER BY city;
+--------+---+
|    city|sum|
+--------+---+
|  Dublin| 33|
| Fremont| 32|
|San Jose| 13|
+--------+---+

-- `HAVING` clause without a `GROUP BY` clause.
SELECT sum(quantity) AS sum FROM dealer HAVING sum(quantity) > 10;
+---+
|sum|
+---+
| 78|
+---+