What are the methods for extracting substrings in Oracle?

2 years ago
Olivia Parker
2 minutes

There are several ways to extract a substring from a string in Oracle database.

  1. SUBSTR function: This function is used to extract a specified length of substring from a string. The syntax is: SUBSTR(string, start_position, length)
  2. string: the string to be trimmed
  3. start_position: the beginning point for the extraction (counting from 1)
  4. cutting length
  5. INSTR function: This function is used to locate the position of a specified substring in a string. The syntax is: INSTR(string, substring, start_position, occurrence)
  6. String: The string to be searched for.
  7. substring: the substring to be searched for
  8. Starting position: the location where the search begins, counting from 1.
  9. occurrence: specifies the position of the substring to be searched for, with a default value of 1.
  10. The SUBSTRING function is available in Oracle 12c and above, and is used to extract a specified length of characters from a string. The syntax is: SUBSTRING(string FROM start_position FOR length)
  11. string: string to be trimmed
  12. starting position: the position where the extraction begins (counting from 1)
  13. cutting length
  14. The REGEXP_SUBSTR function is used to extract a substring from a string using a regular expression. The syntax is: REGEXP_SUBSTR(string, pattern, position, occurrence, match_parameter)
  15. String: the string from which to extract a substring
  16. regular expression used to match substrings
  17. position: designate the starting point for matching within the string (counting from 1)
  18. ocurrence: specifies which match of the substring to return, default is 1
  19. match_parameter: parameter to specify the matching rule

These methods can be selected and used according to needs, choosing the most suitable method for string truncation based on the actual situation.

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