How can you use regexp_substr to extract characters in Oracle?

1 year ago
Ava Mitchell
2 minutes

In Oracle, you can use the REGEXP_SUBSTR function to extract characters. This function uses regular expressions to match strings and return the substring that meets the criteria.

Here is the basic syntax for using the REGEXP_SUBSTR function to extract characters:

Retrieve a substring from a column based on a certain pattern in a specified table under certain conditions.

Among them:

  1. “column_name is the name of the column you want to extract characters from.”
  2. “pattern is a regular expression pattern used to match substrings that meet certain conditions.”
  3. table_name is the name of the table you want to query.
  4. “Condition is the query criteria used to filter data.”

Here are some examples:

  1. Extract numbers from the string:
    SELECT REGEXP_SUBSTR(‘abc123def456’, ‘[0-9]+’)
    FROM dual;
    The output result is: 123
  2. Extract the alphabetic characters from a string:
    SELECT REGEXP_SUBSTR(‘abc123def456’, ‘[a-zA-Z]+’)
    FROM dual;
    The output result is: abc
  3. Extract specific characters from a string:
    SELECT REGEXP_SUBSTR(‘abc123def456’, ‘123|def’)
    FROM dual;
    The output result is: 123

Please note that the REGEXP_SUBSTR function only returns the first substring that meets the condition. If you want to extract multiple substrings, you can use the fourth parameter of the REGEXP_SUBSTR function to specify the position of the substring to return.

For more detailed information, please refer to the official Oracle documentation at: https://docs.oracle.com/cd/B19306_01/server.102/b14200/functions130.htm

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