MaxCompute:SQRT

Syntax

double|decimal sqrt(<number>)

Parameters

number: Required. Accepts DOUBLE or DECIMAL values. STRING and BIGINT values are implicitly converted to DOUBLE before evaluation. The value must be greater than 0; values that are 0 or negative return NULL.

Return value

The return type mirrors the input type:

• DOUBLE input → DOUBLE

• DECIMAL input → DECIMAL

• STRING or BIGINT input → DOUBLE (after implicit type conversion)

• NULL input → NULL

Examples

Static examples:

-- Returns 2.0
SELECT sqrt(4);

-- Returns NULL
SELECT sqrt(null);

Column query:

Use the following sample table to test sqrt against different data types and edge cases:

CREATE TABLE IF NOT EXISTS mf_math_fun_t(
    int_data     INT,
    bigint_data  BIGINT,
    double_data  DOUBLE,
    decimal_data DECIMAL,
    float_data   FLOAT,
    string_data  STRING
);

INSERT INTO mf_math_fun_t VALUES
(null, -10, 0.525, 0.525BD, CAST(0.525 AS FLOAT), '10'),
(-20, null, -0.1, -0.1BD, CAST(-0.1 AS FLOAT), '-10'),
(0, -1, null, 20.45BD, CAST(-1 AS FLOAT), '30'),
(-40, 4, 0.89, null, CAST(0.89 AS FLOAT), '-30'),
(5, -50, -1, -1BD, null, '50'),
(-60, 6, 1.5, 1.5BD, CAST(1.5 AS FLOAT), '-50'),
(-1, -70, -7.5, -7.5BD, CAST(-7.5 AS FLOAT), null),
(-80, 1, -10.2, -10.2BD, CAST(-10.2 AS FLOAT), '-1'),
(9, -90, 2.58, 2.58BD, CAST(2.58 AS FLOAT), '0'),
(-100, 10, -5.8, -5.8BD, CAST(-5.8 AS FLOAT), '-90');

Calculate the square root across multiple typed columns:

SELECT
    sqrt(bigint_data)  AS bigint_new,
    sqrt(double_data)  AS double_new,
    sqrt(decimal_data) AS decimal_new,
    sqrt(string_data)  AS string_new
FROM mf_math_fun_t;

Result:

+--------------------+--------------------+-------------------+--------------------+
| bigint_new         | double_new         | decimal_new       | string_new         |
+--------------------+--------------------+-------------------+--------------------+
| NULL               | 0.724568837309472  | 0.724568837309472 | 3.1622776601683795 |
| NULL               | NULL               | NULL              | NULL               |
| NULL               | NULL               | 4.522167621838006 | 5.477225575051661  |
| 2.0                | 0.9433981132056604 | NULL              | NULL               |
| NULL               | NULL               | NULL              | 7.0710678118654755 |
| 2.449489742783178  | 1.224744871391589  | 1.224744871391589 | NULL               |
| NULL               | NULL               | NULL              | NULL               |
| 1.0                | NULL               | NULL              | NULL               |
| NULL               | 1.606237840420901  | 1.606237840420901 | 0.0                |
| 3.1622776601683795 | NULL               | NULL              | NULL               |
+--------------------+--------------------+-------------------+--------------------+

NULL results appear for negative inputs and for string values that cannot be converted to a positive number.

Related functions

SQRT is a mathematical function. For other mathematical functions, see Mathematical functions.