Update DBMS/SQL/Week4/writeup.md

DBMS/SQL/Week4/writeup.md

@@ -1 +1,76 @@
-## Lab 4 - OracleDB
+## Lab 4 - OracleDB
+
+### Verifying the existence of the previous labs' DB.
+```sql
+SQL> select table_name from user_tables;
+
+TABLE_NAME
+--------------------------------------------------------------------------------
+ACCIDENT
+CAR
+OWNS
+PARTICIPATED
+PERSON
+```
+
+### Q1. Find the total number of people who owned cars that were involved in accidents in 2008.
+
+Ans. 
+
+Modifying the table to add required entry from 2008.
+```sql
+
+SQL> select * from accident;
+
+REPORT_NUMBER ACCD_DATE LOCATION
+------------- --------- --------------------------------------------------
+            1 01-JAN-24 Delhi India
+            3 29-FEB-24  India
+            5 31-MAR-00  Gujrat India
+           12 17-JUL-00  karnataka India
+           10 01-JAN-08 Manipal India
+
+SQL> update accident set ACCD_DATE='01-Jan-2008' where REPORT_NUMBER=1
+  2  ;
+
+1 row updated.
+
+SQL> select * from accident;
+
+REPORT_NUMBER ACCD_DATE LOCATION
+------------- --------- --------------------------------------------------
+            1 01-JAN-08 Delhi India
+            3 29-FEB-24  India
+            5 31-MAR-00  Gujrat India
+           12 17-JUL-00  karnataka India
+           10 01-JAN-08 Manipal India
+```
+
+
+```sql
+SQL> select count(distinct Driver_ID#) from participated natural join accident where extract(year from accd_date)=2008;
+
+COUNT(DISTINCTDRIVER_ID#)
+-------------------------
+                        1
+```
+
+### Q2. Find the number of accidents in which cars belonging to a specific model were involved.
+```sql
+SQL> select * from car;
+
+REGNO                MODEL                                YEAR
+-------------------- ------------------------------ ----------
+ABCD0001             Celtos                                  3
+EFGH2001             Ferrari                                32
+DSDS0001             Urus                                    5
+ABCD4001             Honda City                              1
+HFSP5601             mini cooper                             7
+
+SQL> select count(distinct driver_id#) from car natural join participated where model like 'Urus';
+
+COUNT(DISTINCTDRIVER_ID#)
+-------------------------
+                        1
+```
+