What function is used to define a certain character in Oracle?

Use the INSTR function in Oracle to check whether a string contains specific characters. Syntax: INSTR(string, substring, [start_position], [occurrence]). It returns the index position of the first occurrence of the substring in the string, or 0 if no match is found.

Function containing specific characters in Oracle: INSTR

In Oracle, you can use INSTR Function to check whether a string contains another string.

Syntax

<code>INSTR(string, substring, [start_position], [occurrence])</code>

Parameters

• string: The string to search for.
• substring: The substring to find.
• start_position (optional): The position to start searching for the substring (default 1).
• occurrence (optional): The occurrence of the substring to find (defaults to the first occurrence).

Usage

INSTR The function returns the index position of the first occurrence of the substring in the string. Returns 0 if no match is found.

For example, the following query finds the first occurrence of the character 'o' in the string 'Hello World':

<code>SELECT INSTR('Hello World', 'o') FROM dual;</code>

Output:

<code>4</code>

This means that the character 'o' is at index 4 in the string 'Hello World'.

Note

• The index position in the string starts from 1, not 0.
• If start_position is greater than the length of the string, the INSTR function will return 0.
• The INSTR function returns 0 if occurrence is greater than the number of times the substring occurs in the string.

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