4. You are working with a database table that contains invoice data. The table includes columns for invoice_id and billing state. You want to remove duplicate entries for billing state and sort the results by invoice ID. You write the SQL query below. Add a DISTINCT clause that will remove duplicate entries from the billing state column. NOTE: The three dots (...) indicate where to add the clause. 1 SELECT ...Distinct operator 2 FROM 3 invoice Run ORDER BY invoice_id Reset 4 5

Given the table PRODUCT(ProductID, ProductName, ProductClass, ProductWeight, ProductStyle, ProductColor, ProductPrice). Note: ProductWeight and ProductPrice are numeric fields, and the other attributes are character fields, i.e., store text. Write a SQL query to display the product class whose average price is at least 50

Write a SQL statement to create a table job_history including columns employee_id, start_date, end_date, job_id and department_id and make sure that, the employee_id column does not contain any duplicate value at the time of insertion and the foreign key column job_id contain only those values which are exists in the jobs table. Field EMPLOYEE_ID START_DATE END DATE JOB_ID DEPARTMENT_ID Type Decimal(6,0) Date Date Varchar(10) Decimal(4,0) Null No No No No Yes Key pk fk Default Extra Null Null Null Null Null

Practice 1 (continued) 7. Show the structure of the EMP table. Create a query to display the name, job. hire date, and employee number for each employee, with employee number appearing first. Save your SQL statement to a file named plq7.sql. Name Null? Туре EMPNO NOT NULL NUMBER(4) ENAME VARCHAR2(10) JOB VARCHAR2(9) MGR NUMBER(4) HIREDATE DATE SAL NUMBER(7,2) СOMM NUMBER(7,2) DEPTNΟ NUMBER(2) 8. Run your query in the file plq7.sql. EMPNO ENAME JOB HIREDATE 7369 SMITH CLERK 17/12/1980 7499 ALLEN SALESMAN 20/02/1981 7521 WARD SALESMAN 22/02/1981 7566 JONES ΜΑΝAGER 02/04/1981 7654 MARTIN SALESMAN 28/09/1981 7698 BLAKE MANAGER 01/05/1981 7782 CLARK MANAGER 09/06/1981 7788 SCOTT ANALYST 09/12/1982 7839 KING PRESIDENT 17/11/1981 7844 TURNER SALESMAN 08/09/1981 7876 ADAMS CLERK 12/01/1983 7900 JAMES CLERK 03/12/1981 7902 FORD ANALYST 03/12/1981 7934 MILLER CLERK 23/01/1982 14 rows selected.