COUNT_BY_ENUM

Description

Treat the data in the column as enumeration values and count the number of each enumeration value. Returns the number of enumeration values for each column, as well as the number of non-null values and the number of null values.

Syntax

COUNT_BY_ENUM(<expr1>, <expr2>, ... , <exprN>)

Parameters

Parameter	Description
<expr1>	Fill in at least one input. Column whose value is of type STRING

Returned value

Returns a JSONArray string.

For example:

[{
  "cbe": {
    "F": 100,
    "M": 99
  },
  "notnull": 199,
  "null": 1,
  "all": 200
}, {
  "cbe": {
    "20": 10,
    "30": 5,
    "35": 1
  },
  "notnull": 16,
  "null": 184,
  "all": 200
}, {
  "cbe": {
    "China": 10,
    "United States": 9,
    "England": 20,
    "Germany": 30
  },
  "notnull": 69,
  "null": 131,
  "all": 200
}]

Description: The return value is a JSON array string and the order of the internal objects is the order of the input parameters.

• cbe: count of non-null values based on enumeration values
• notnull: number of non-null values.
• null: number of null values
• all: total number, including both null and non-null values.

Example

CREATE TABLE count_by_enum_test(
                                   `id` varchar(1024) NULL,
                                   `f1` text REPLACE_IF_NOT_NULL NULL,
                                   `f2` text REPLACE_IF_NOT_NULL NULL,
                                   `f3` text REPLACE_IF_NOT_NULL NULL
)
AGGREGATE KEY(`id`)
DISTRIBUTED BY HASH(id) BUCKETS 3 
PROPERTIES ( 
    "replication_num" = "1"
);

INSERT into count_by_enum_test (id, f1, f2, f3) values
                                                    (1, "F", "10", "China"),
                                                    (2, "F", "20", "China"),
                                                    (3, "M", NULL, "United States"),
                                                    (4, "M", NULL, "United States"),
                                                    (5, "M", NULL, "England");

SELECT * from count_by_enum_test;

+------+------+------+---------------+
| id   | f1   | f2   | f3            |
+------+------+------+---------------+
| 1    | F    | 10   | China         |
| 2    | F    | 20   | China         |
| 3    | M    | NULL | United States |
| 4    | M    | NULL | United States |
| 5    | M    | NULL | England       |
+------+------+------+---------------+

select count_by_enum(f1) from count_by_enum_test;

+------------------------------------------------------+
| count_by_enum(`f1`)                                  |
+------------------------------------------------------+
| [{"cbe":{"M":3,"F":2},"notnull":5,"null":0,"all":5}] |
+------------------------------------------------------+

select count_by_enum(f2) from count_by_enum_test;

+--------------------------------------------------------+
| count_by_enum(`f2`)                                    |
+--------------------------------------------------------+
| [{"cbe":{"10":1,"20":1},"notnull":2,"null":3,"all":5}] |
+--------------------------------------------------------+

select count_by_enum(f1,f2,f3) from count_by_enum_test;

+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| count_by_enum(`f1`, `f2`, `f3`)                                                                                                                                                          |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| [{"cbe":{"M":3,"F":2},"notnull":5,"null":0,"all":5},{"cbe":{"20":1,"10":1},"notnull":2,"null":3,"all":5},{"cbe":{"England":1,"United States":2,"China":2},"notnull":5,"null":0,"all":5}] |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+