multi_distinct_sum

Description

Returns the sum of distinct values in expr, equivalent to sum(distinct expr).

Syntax

multi_distinct_sum(expr)

Parameters

• expr: the columns involved in the calculation. Column values can be of the following types: TINYINT, SMALLINT, INT, LARGEINT, FLOAT, DOUBLE, or DECIMAL.

Return value

The mapping between column values and return value types is as follows:

• BOOLEAN -> BIGINT
• TINYINT -> BIGINT
• SMALLINT -> BIGINT
• INT -> BIGINT
• BIGINT -> BIGINT
• FLOAT -> DOUBLE
• DOUBLE -> DOUBLE
• LARGEINT -> LARGEINT
• DECIMALV2 -> DECIMALV2
• DECIMAL32 -> DECIMAL128
• DECIMAL64 -> DECIMAL128
• DECIMAL128 -> DECIMAL128

Examples

1. Create a table with k0 as the INT field.

   CREATE TABLE tabl
   (k0 BIGINT NOT NULL) ENGINE=OLAP
   DUPLICATE KEY(`k0`)
   COMMENT "OLAP"
   DISTRIBUTED BY HASH(`k0`)
   PROPERTIES(
       "replication_num" = "3",
       "storage_format" = "DEFAULT"
   );

2. Insert values into the table.

   -- 
   INSERT INTO tabl VALUES ('0'), ('1'), ('1'), ('1'), ('2'), ('2');

3. Use multi_distinct_sum() to calculate the sum of distinct values in the k0 column.

   MySQL > select multi_distinct_sum(k0) from tabl;
   +------------------------+
   | multi_distinct_sum(k0) |
   +------------------------+
   |                      3 |
   +------------------------+
   1 row in set (0.03 sec)

   The distinct values of k0 is 0, 1, 2 and we can get 3 after adding them together.