TO_DATE function is used to convert a string to an Oracle date type. It takes two parameters: the string expression to convert and a format mask specifying the string format. Common format masks include 'DD-MON-YY' (e.g. '12-JAN-23'), 'YYYY-MM-DD' (e.g. '2023-01-12') and 'HH24:MI:SS' (e.g. '12-JAN-23') For example '13:30:00'). Use a format mask to select the correct format to convert a string into a date value.
Usage of TO_DATE function in Oracle
TO_DATE function is used to convert a string to Oracle date type. It is useful for converting character data received from an external source, such as a file or web service, into a date value.
Syntax:
<code>TO_DATE(string_expression, format_mask)</code>
Parameters:
- string_expression: To be converted to date string expression.
- format_mask: A format mask that specifies the format of a string expression.
Format masks:
Oracle provides various format masks to specify the date format of string expressions. Here are some of the most commonly used masks:
- 'DD-MON-YY': day-month-year, e.g. '12-JAN-23'
- 'DD-MM-YY': Day-month-year, for example '12-01-23'
- 'YYYY-MM-DD': Year-month-day, for example, '2023-01-12'
- 'HH24:MI:SS': Hour-minute-second, for example, '13:30:00'
Usage:
The usage of TO_DATE function is as follows:
- Determine the format of the input string.
- Choose an appropriate format mask.
- Use syntax to convert a string to a date value.
Example:
The following example will convert '2023-01-12' to a date value:
<code>SELECT TO_DATE('2023-01-12', 'YYYY-MM-DD') FROM dual;</code>
The result will be a DATE Value: '2023-01-12'.
Note:
- The TO_DATE function will return an error if the string expression does not match the specified format mask.
- The format mask is case-sensitive and must be specified as-is.
- The TO_DATE function returns an error if the string expression contains an invalid date value.
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