subtr oracle 3f

1-- ORACLE substr(string, start, [, length ])
2SELECT substr('Hello World', 4, 5) FROM DUAL;       -- lo Wo
3SELECT substr('Hello World', 4) FROM DUAL;          -- lo World
4SELECT substr('Hello World', -3) FROM DUAL;         -- rld
5SELECT substr('Hello World', -3, 2) FROM DUAL;      -- rl

1/*Using SUBSTR in Oracle (Example from hackerrank.com): */
2
3/*Simple select query...*/ 
4SELECT DISTINCT city 
5FROM station 
6
7/*Using WHERE and SUBSTR to find (distinct) cities in station table that begin 
8as well as end with a vowel.*/ 
9WHERE SUBSTR(city,1,1) IN ('A','E','I','O','U') 
10	AND substr(city,-1) IN ('a','e','i','o','u'); 
11
12/*Parameters for SUBSTR (Substring) in order are as follows: 
13String, Start, Length.*/