How to retrieve specific characters within rows of database column? Which Oracle SQL query is preferred or ideal to return the second, third and fourth positioned characters within rows of a particular column? A SQL statement using the SUBSTR method or some type of REGEX?

The following is the query I am trying to use:

SELECT REGEXP_SUBSTR(city) 
FROM student.zip;


I would appreciate any recommendations-thanks!
Your question's not brilliantly clear, but if you want the 2nd, 3rd and 4th characters in the column city, in the table zip, then use SUBSTR:

SELECT SUBSTR(city,2,3) 
FROM student.zip;


REGEXP_INSTR returns the location of a match, not a string, so you don't want to use that. REGEXP_MATCH would be the one to use, but SUBSTR is simpler.