Oracle Intercept character (SUBSTR), retrieving character position (instr)

Common functions: Substr and InStr

1.SUBSTR (String,start_position,[length]) to substring, return string

Explanation: String meta strings

Start_position start position (starting from 0)

Length optional, number of substrings

For example:

substr ("ABCDEFG", 0); return: ABCDEFG, intercept all characters

substr ("ABCDEFG", 2); return: CDEFG, intercept all characters after starting with C

substr ("ABCDEFG", 0, 3); return: ABC, intercept starting from a 3 characters

substr ("ABCDEFG", 0, 100); Return: abcdefg,100 The maximum number of preprocessed strings is returned, although it exceeds the length of the preprocessed string, but does not affect the return result.

substr ("ABCDEFG",-3); Return: EFG, note parameter-3, a negative value indicates that the string is not changed from the beginning of the tail.

2.INSTR (string,substring,position,ocurrence) Find string position

Explanation: string: source string

SubString: substring to find

Position: Where to find start

Ocurrence: A substring of the first occurrence of a source string

For example:

INSTR (' CORPORATE floor ', ' or ', 3, 2), the source string is ' CORPORATE floor ', the target string is ' OR ', the starting position is 3, the position of the 2nd match is taken, and the return result is 14 '

Oracle Intercept character (SUBSTR), retrieving character position (instr)