Usage of cast function in oracle

The CAST function is used to explicitly convert a value to another data type, with the syntax CAST(expression AS data_type). Usage examples include: convert numeric value to string, string to date, and string to number. Conversion options include numeric, character, date, and boolean types.

Usage of CAST function in Oracle

Introduction to CAST function

The CAST function is used to explicitly convert a value of one data type to another data type. The syntax is as follows:

<code>CAST(expression AS data_type)</code>

Where:

• expression: The value to be converted
• data_type: To be converted To the data type

Usage example

Convert a numerical value to a string

<code>SELECT CAST(123.45 AS VARCHAR2(20)) FROM dual;</code>

Result: '123.45'

Convert string to date

<code>SELECT CAST('2023-01-01' AS DATE) FROM dual;</code>

Result: 2023-01-01

Convert string to number

<code>SELECT CAST('1,234.56' AS NUMBER) FROM dual;</code>

Result: 1234.56

Type conversion options

The CAST function supports multiple data type conversions, including:

• Numeric types: NUMBER, INT, FLOAT, etc.
• Character types: VARCHAR2, CHAR, etc.
• Date types : DATE, TIMESTAMP, etc.
• Boolean type: BOOLEAN

Notes

• CAST function conversion does not modify the original value , it will only return the converted result.
• When the conversion fails, an error will be thrown. Make sure the value being converted is compatible with the target data type.
• When using the CAST function, it is important to specify the number of digits or precision occupied by the target data type to ensure an accurate conversion.

The above is the detailed content of Usage of cast function in oracle. For more information, please follow other related articles on the PHP Chinese website!