RETENTION

SinceVersion 1.2.0

RETENTION

description

Syntax

retention(event1, event2, ... , eventN);

留存函数将一组条件作为参数，类型为1到32个UInt8类型的参数，用来表示事件是否满足特定条件。 任何条件都可以指定为参数.

除了第一个以外，条件成对适用：如果第一个和第二个是真的，第二个结果将是真的，如果第一个和第三个是真的，第三个结果将是真的，等等。

简单来讲，返回值数组第1位表示event1的真假，第二位表示event1真假与event2真假相与，第三位表示event1真假与event3真假相与，等等。如果event1为假，则返回全是0的数组。

Arguments

event — 返回UInt8结果（1或0）的表达式.

Returned value

由1和0组成的最大长度为32位的数组，最终输出数组的长度与输入参数长度相同。

1 — 条件满足。

0 — 条件不满足

example

DROP TABLE IF EXISTS retention_test;
CREATE TABLE retention_test(
                `uid` int COMMENT 'user id', 
                `date` datetime COMMENT 'date time' 
                )
DUPLICATE KEY(uid) 
DISTRIBUTED BY HASH(uid) BUCKETS 3 
PROPERTIES ( 
    "replication_num" = "1"
); 
INSERT into retention_test (uid, date) values (0, '2022-10-12'),
                                        (0, '2022-10-13'),
                                        (0, '2022-10-14'),
                                        (1, '2022-10-12'),
                                        (1, '2022-10-13'),
                                        (2, '2022-10-12'); 
SELECT * from retention_test;
+------+---------------------+
| uid  | date                |
+------+---------------------+
|    0 | 2022-10-14 00:00:00 |
|    0 | 2022-10-13 00:00:00 |
|    0 | 2022-10-12 00:00:00 |
|    1 | 2022-10-13 00:00:00 |
|    1 | 2022-10-12 00:00:00 |
|    2 | 2022-10-12 00:00:00 |
+------+---------------------+
SELECT 
    uid,     
    retention(date = '2022-10-12')
        AS r 
            FROM retention_test 
            GROUP BY uid 
            ORDER BY uid ASC;
+------+------+
| uid  | r    |
+------+------+
|    0 | [1]  | 
|    1 | [1]  |
|    2 | [1]  |
+------+------+
SELECT 
    uid,     
    retention(date = '2022-10-12', date = '2022-10-13')
        AS r 
            FROM retention_test 
            GROUP BY uid 
            ORDER BY uid ASC;
+------+--------+
| uid  | r      |
+------+--------+
|    0 | [1, 1] |
|    1 | [1, 1] |
|    2 | [1, 0] |
+------+--------+
SELECT 
    uid,     
    retention(date = '2022-10-12', date = '2022-10-13', date = '2022-10-14')
        AS r 
            FROM retention_test 
            GROUP BY uid 
            ORDER BY uid ASC;
+------+-----------+
| uid  | r         |
+------+-----------+
|    0 | [1, 1, 1] |
|    1 | [1, 1, 0] |
|    2 | [1, 0, 0] |
+------+-----------+

keywords

RETENTION