Common String Functions in Oracle SQL

  • UPPER(), LOWER(), INITCAP() – change case
  • SUBSTR(str, start, length) – extract substring
  • INSTR(str, substr) – find position
  • LENGTH(str) – length of string
  • CONCAT(str1, str2) – combine strings
SELECT UPPER('oracle'), LENGTH('sql functions'), SUBSTR('Hello World', 1, 5) FROM dual;