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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.