1. Which of the following query is correct for using comparison operators in SQL?A) SELECT sname, coursename FROM studentinfo WHERE age>50 and <80;B) SELECT sname, coursename FROM studentinfo WHERE age>50 and age <80;C) SELECT sname, coursename FROM studentinfo WHERE age>50 and WHERE age<80;D) None of the above2.How to select all data from studentinfo table starting the name from letter 'r'?A) SELECT * FROM studentinfo WHERE sname LIKE 'r%';B) SELECT * FROM studentinfo WHERE sname LIKE '%r%';C) SELECT * FROM studentinfo WHERE sname LIKE '%r';D) SELECT * FROM studentinfo WHERE sname LIKE '_r%';3. Which of the following SQL query is correct for selecting the name of staffs from 'tblstaff' table where salary is 15,000 or 25,000?A) SELECT sname from tblstaff WHERE salary...