Usage of substr function in oracle

The substr() function extracts a substring of a string. The syntax is: substr(str, start, [length]). Usage example: Extract the 4 characters starting from the 3rd character from 'Hello World': SELECT substr('Hello World', 3, 4) FROM dual; Result: 'llo'.

Usage of substr() function in Oracle

The substr() function is used to extract substrings from strings . The syntax is as follows:

<code>substr(str, start, [length])</code>

Where:

• str: The string from which the substring is to be extracted.
• start: Extract the starting position of the substring, counting from 1.
• length (optional): The length of the substring to be extracted. If omitted, everything from the starting position to the end of the string is extracted.

Usage example

<code>SELECT substr('Hello World', 3, 4) FROM dual;</code>

Output:

<code>llo </code>

Example description:

• This query extracts a 4-character substring starting from the 3rd character ('l') from the string 'Hello World'.
• The result substring is "llo".

Other usage examples:

• Extract the first character of the string:

  <code>SELECT substr('Oracle', 1, 1) FROM dual;</code>

• Extract the last few characters of the string:

  <code>SELECT substr('Database', -3) FROM dual;</code>

• Extract the substring of the specified length:

  <code>SELECT substr('Programming', 1, 8) FROM dual;</code>

Note:

• start parameter must be greater than or equal to 1.
• length parameter must be greater than or equal to 0.
• If start length > string length, only the characters from start to the end of the string will be extracted.
• If start or length is negative, NULL will be returned.

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