SQL Interview questions
Q.What is the use of the DROP option in the ALTER TABLE comm&?
It is used to drop constraints specified on the table.
Q. What is the value of ‘comm’ & ‘sal’ after executing the following query if the initial
value of ‘sal’ is 10000?
UPDATE EMP SET SAL = SAL + 1000, COMM = SAL*0.1;
sal = 11000, comm = 1000 .
Q. Why does the following comm& give a compilation error?
DROP TABLE &TABLE_NAME;
Variable names should start with an alphabet. Here the table name starts with an '&' symbol.
Q. What is the advantage of specifying WITH GRANT OPTION in the GRANT comm& in sql?
The privilege receiver can further grant the privileges he/she has obtained from the owner to any other user.
Q. What is the use of DESC in SQL?
Answer:DESC has two purposes. It is used to describe a schema as well as to retrieve rows from table in descending order.
The query SELECT * FROM EMP ORDER BY ENAME DESC will display the output sorted on ENAME in descending order.
Q. What is the use of CASCADE CONSTRAINTS?
When this clause is used with the DROP comm&, a parent table can be dropped even when a child table exists.