SQL CAST Function Example

SQL CAST is an inbuilt function that is used for converting an expression from one data type to another data type. Here, if the conversion takes place, then a value with specified conversion will be returned. Otherwise, the function will return an error.

SQL CAST

The CAST() function converts a value (of any type) into a specified datatype.

Syntax

CAST (expression AS type [ (length)])

Parameters

1. Expression: The value to be converted to another datatype.
2. Type: The data type to which the expression will be converted.
3. Length: It is entirely optional. It signifies the length of the resulting data type for expression.

Note

1. The result is truncated when an expression is converted to integer datatype when converted from float or integer.
2. For other conversions, the value is rounded.

Examples

SELECT CAST (10.85 AS int);

Output

10

Explanation

As the expression is converted from float to integer. So, the result here is truncated.

Query 2

SELECT CAST (10.85 AS float);

Output

10.85

Explanation

As the expression is converted to float datatype. So, the result here is not truncated, and the original expression was returned, which was already in the float.

Query 3

SELECT CAST (15.6 AS varchar);

Output

'15.6'

Explanation

Here, the floating expression was converted to character datatype.

Query 4

SELECT CAST ('15.6' AS float);

Output

15.6

Explanation

Here, the character data type is converted to a floating-point value.

Query 5

SELECT CAST (5.95 AS DEC (3,0));

Output

6

Explanation

Here, the decimal expression is converted to another decimal expression with different lengths.

Query 6

SELECT CAST ('2020-02-26' AS datetime);

Output

'2020-02-26 00:00:00.000'

Explanation

Here, the string expression is converted to datetime expression.

See also

SQL SESSION_USER

SQL SYSTEM_USER

SQL USER_NAME

SQL CURRENT_USER