Ans: ROWID is a pseudo column attached to each row of a table. It is 18 characters long, block no, row number are the components of ROWID.

Ans: INTERSECT – returns all distinct rows selected by both queries. MINUS – returns all distinct rows selected by the first query but not by the second. UNION – returns all distinct rows selected by either query UNION ALL – returns all rows selected by either query, including all duplicates.

Ans: INSTR (String1, String2 (n, (m)),
INSTR returns the position of the m-th occurrence of the string 2 in string1. The search begins from nth position of string1.
SUBSTR (String1 n, m)
SUBSTR returns a character string of size m in string1, starting from n-th position of string1

Ans: Retrieves rows in hierarchical order Eg. Select empno, ename from EMP where.

Ans: Correlated sub-query is a sub-query, which has reference to the main query.

Ans: Sub-query is a query whose return values are used in filtering conditions of the main query.

Ans: TRUNCATE commits after deleting entire table i.e., cannot be rolled back. Database triggers do not fire on TRUNCATE
DELETE allows the filtered deletion. Deleted records can be rolled back or committed. Database triggers fire on DELETE.

Ans: SQL injection is when from data contains an SQL escape sequence and injects a new SQL query to be run.

Ans: &

Ans: 1200