COUNT_BY_ENUM

Description

Syntax

count_by_enum(expr1, expr2, ... , exprN);

Treats the data in a column as an enumeration and counts the number of values in each enumeration. Returns the number of enumerated values for each column, and the number of non-null values versus the number of null values.

Arguments

expr1 — At least one input must be specified. The value is a column 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

DROP TABLE IF EXISTS count_by_enum_test;
 
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}] |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

keywords

COUNT_BY_ENUM

COUNT COVAR_SAMP