In Oracle, you should use the `INSTR` operate to examine if a personality exists inside a string. The `INSTR` operate takes two arguments: the substring you wish to discover, and the string you wish to search inside. If the substring is discovered inside the string, the `INSTR` operate will return the place of the primary prevalence of the substring. If the substring isn’t discovered, the `INSTR` operate will return 0.
For instance, the next question would examine if the character ‘a’ exists inside the string ‘Good day, world!’: