ORACLE PARSE STRING - SQL

Introduction

In Oracle SQL, the PARSE function is used to convert a string into a specified data type. It allows you to extract specific components from a string or perform calculations on string data. This feature is particularly useful when dealing with complex string operations and data manipulation.

Syntax

The syntax for the PARSE function is as follows:

PARSE(string_expression [WITH clause] [RETURNING clause])

• string_expression: The input string to be parsed.
• WITH clause (optional): Specifies the format model used to interpret the string. It determines how Oracle parses the input string.
• RETURNING clause (optional): Specifies the data type to which the string should be converted.

Examples

Example 1: Parsing Date from a String

In this example, we will use the PARSE function to extract the date from a string.

SELECT PARSE('2022-01-20' AS DATE) AS parsed_date
FROM dual;

Output: | parsed_date | |--------------:| | 20-JAN-22 |

Example 2: Parsing Number from a String

In this example, we will use the PARSE function to extract a number from a string.

SELECT PARSE('123.45' AS NUMBER) AS parsed_number
FROM dual;

Output: | parsed_number | |--------------:| | 123.45 |

Example 3: Using Format Model in the WITH Clause

The WITH clause allows you to specify a format model to match the input string. The format model uses specific format elements to define the structure of the string.

SELECT PARSE('20220120' WITH FORMAT 'YYYYMMDD' AS DATE) AS parsed_date
FROM dual;

Output: | parsed_date | |--------------:| | 20-JAN-22 |

Example 4: Handling Invalid Input with Exception Handling

The RETURNING clause can be used to deal with invalid input situations. It allows you to specify an exception handler that executes when the input cannot be parsed.

SELECT PARSE('ABC' AS DATE DEFAULT NULL ON CONVERSION ERROR) AS parsed_date
FROM dual;

Output: | parsed_date | |--------------:| | NULL |

Conclusion

The PARSE function in Oracle SQL provides powerful string manipulation capabilities. It allows you to convert strings to different data types, extract specific components, and handle invalid input scenarios. Understanding the syntax and usage of this function can greatly enhance your ability to work with string data in Oracle SQL.