SUM¶

语法¶

聚合函数

SUM( [ DISTINCT ] <expr1> )

窗口函数

SUM( [ DISTINCT ] <expr1> ) OVER (
                                 [ PARTITION BY <expr2> ]
                                 [ ORDER BY <expr3> [ ASC | DESC ] [ <window_frame> ] ]
                                 )

有关 window_frame 语法的详细信息，请参阅 窗口框架语法和用法。

实参¶

expr1

这是一个计算结果为数值数据类型（INTEGER、FLOAT、DECIMAL 等）的表达式。

expr2

这是用于划分分区的可选表达式。

expr3

这是每个分区中作为排序规则的可选表达式。（这不会控制整个查询输出的顺序。）

使用说明¶

• 数值总计为等同的数据类型或较大的数据类型。

• 传递 VARCHAR 表达式时，此函数会将输入隐式转换为浮点值。如果无法执行转换，则会返回错误。

• 当此函数作为窗口函数调用时（即带有 OVER 子句）：

  • 如果 OVER 子句包含 ORDER BY 分子句，则：

    • 需要窗口框架。如果未明确指定窗口框架，则 ORDER BY 默认为累积窗口框架：

      RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW

      有关窗口框架的信息（包括语法和示例），请参阅 窗口框架语法和用法。

      有关隐含窗口框架的信息，另请参阅 窗口框架使用说明。

    • 禁止在窗口函数中使用关键字 DISTINCT，否则会导致编译时错误。

示例¶

CREATE OR REPLACE TABLE sum_example(k INT, d DECIMAL(10,5),
                                    s1 VARCHAR(10), s2 VARCHAR(10));

INSERT INTO sum_example VALUES
(1, 1.1, '1.1','one'), (1, 10, '10','ten'),
(2, 2.2, '2.2','two'), (2, null, null,'null'),
(3, null, null, 'null'),
(null, 9, '9.9','nine');

SELECT * FROM sum_example;

+------+----------+------+------+
|    K |        D | S1   | S2   |
|------+----------+------+------|
|    1 |  1.10000 | 1.1  | one  |
|    1 | 10.00000 | 10.0 | ten  |
|    2 |  2.20000 | 2.2  | two  |
|    2 |     NULL | NULL | null |
|    3 |     NULL | NULL | null |
| NULL |  9.00000 | 9.9  | nine |
+------+----------+------+------+

SELECT SUM(d), SUM(s1) FROM sum_example;

+----------+---------+
|   SUM(D) | SUM(S1) |
|----------+---------|
| 22.30000 |    23.2 |
+----------+---------+

select k, SUM(d), SUM(s1) FROM sum_example GROUP BY k;

+------+----------+---------+
|    K |   SUM(D) | SUM(S1) |
|------+----------+---------|
|    1 | 11.10000 |    11.1 |
|    2 |  2.20000 |     2.2 |
|    3 |     NULL |    NULL |
| NULL |  9.00000 |     9.9 |
+------+----------+---------+

SELECT SUM(s2) FROM sum_example;

100038 (22018): Numeric value 'one' is not recognized

下面的脚本显示了此函数（以及其他一些窗口函数）在窗口上下文中的用法：

CREATE OR REPLACE TABLE example_cumulative (p INT, o INT, i INT);

INSERT INTO example_cumulative VALUES
    (  0, 1, 10), (0, 2, 20), (0, 3, 30),
    (100, 1, 10),(100, 2, 30),(100, 2, 5),(100, 3, 11),(100, 3, 120),
    (200, 1, 10000),(200, 1, 200),(200, 1, 808080),(200, 2, 33333),(200, 3, null), (200, 3, 4),
    (300, 1, null), (300, 1, null);

Copy

SELECT
    p, o, i,
    COUNT(i) OVER (PARTITION BY p ORDER BY o ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) count_i_Rows_Pre,
    SUM(i)   OVER (PARTITION BY p ORDER BY o ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) sum_i_Rows_Pre,
    AVG(i)   OVER (PARTITION BY p ORDER BY o ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) avg_i_Rows_Pre,
    MIN(i)   OVER (PARTITION BY p ORDER BY o ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) min_i_Rows_Pre,
    MAX(i)   OVER (PARTITION BY p ORDER BY o ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) max_i_Rows_Pre
  FROM example_cumulative
  ORDER BY p,o;
+-----+---+--------+------------------+----------------+----------------+----------------+----------------+
|   P | O |      I | COUNT_I_ROWS_PRE | SUM_I_ROWS_PRE | AVG_I_ROWS_PRE | MIN_I_ROWS_PRE | MAX_I_ROWS_PRE |
|-----+---+--------+------------------+----------------+----------------+----------------+----------------|
|   0 | 1 |     10 |                1 |             10 |         10.000 |             10 |             10 |
|   0 | 2 |     20 |                2 |             30 |         15.000 |             10 |             20 |
|   0 | 3 |     30 |                3 |             60 |         20.000 |             10 |             30 |
| 100 | 1 |     10 |                1 |             10 |         10.000 |             10 |             10 |
| 100 | 2 |     30 |                2 |             40 |         20.000 |             10 |             30 |
| 100 | 2 |      5 |                3 |             45 |         15.000 |              5 |             30 |
| 100 | 3 |     11 |                4 |             56 |         14.000 |              5 |             30 |
| 100 | 3 |    120 |                5 |            176 |         35.200 |              5 |            120 |
| 200 | 1 |  10000 |                1 |          10000 |      10000.000 |          10000 |          10000 |
| 200 | 1 |    200 |                2 |          10200 |       5100.000 |            200 |          10000 |
| 200 | 1 | 808080 |                3 |         818280 |     272760.000 |            200 |         808080 |
| 200 | 2 |  33333 |                4 |         851613 |     212903.250 |            200 |         808080 |
| 200 | 3 |   NULL |                4 |         851613 |     212903.250 |            200 |         808080 |
| 200 | 3 |      4 |                5 |         851617 |     170323.400 |              4 |         808080 |
| 300 | 1 |   NULL |                0 |           NULL |           NULL |           NULL |           NULL |
| 300 | 1 |   NULL |                0 |           NULL |           NULL |           NULL |           NULL |
+-----+---+--------+------------------+----------------+----------------+----------------+----------------+

Copy