Adding homeworks from weeks 3 and 4.

practiceProblems/week3/ch5_DML_Transactions/answers.pks

@@ -10,6 +10,11 @@ constraints (PK, NOT NULL, CHECK, UNIQUE). Use the DESCRIBE command
 to verify that the columns have been defined correctly.
 */
 
+CREATE TABLE MICHAEL_LUNDQUIST (ID integer, firstName VARCHAR2(20) NOT NULL, lastName VARCHAR2(20) NOT NULL, addDay DATE DEFAULT SYSDATE, zip CHAR(5) NOT NULL, CONSTRAINT MICHAEL_LUNDQUIST_ID_pk PRIMARY KEY (ID));
+
+DESC MICHAEL_LUNDQUIST;
+
+
 /*
 problem2
 
@@ -22,6 +27,8 @@ command to display the content of the table
 table).
 */
 
+INSERT INTO MICHAEL_LUNDQUIST values (1, 'Michael', 'Lundquist', DEFAULT, '20194');
+
 /*
 problem3
 
@@ -33,6 +40,8 @@ command to display the content of the table
 (make sure to substitute your_table_name with the actual name of your table).
 */
 
+INSERT INTO MICHAEL_LUNDQUIST (ID, firstName, lastName, addDay, zip) values (0, 'Michael', 'Lundquist', DEFAULT, '20194');
+
 /*
 problem4
 
@@ -44,6 +53,8 @@ command to display the content of the table
 table).
 */
 
+UPDATE MICHAEL_LUNDQUIST SET LASTNAME = 'coolGuy' where LASTNAME = 'Lundquist';
+
 /*
 problem5
 
@@ -55,6 +66,8 @@ command to display the content of the table
 table).
 */
 
+DELETE FROM MICHAEL_LUNDQUIST WHERE ID = 0;
+
 /*
 problem6
 
@@ -64,6 +77,8 @@ content of the table (make sure to substitute your_table_name with the
 actual name of your table).
 */
 
+COMMIT;
+
 /*
 problem7
 
@@ -75,7 +90,17 @@ command to display the content of the table
 table).
 */
 
+/*
+DDL commands can't be rolled back
+uncommitted DML commands are deleted
+we just committted, so nothing
+*/
+
+ROLLBACK;
+
 /*
 problem8
 Use the DROP TABLE command to drop the table created in Problem 1.
 */
+
+DROP TABLE MICHAEL_LUNDQUIST;
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practiceProblems/week3/ch5_DML_Transactions/ch5_answers.md

+# ch 5 DML
+
+## problem 1
+
+Create a new table using the CREATE TABLE command. Use your first name
+and your last name for the name of the table 
+(for instance, for John Smith the name of the table will be JOHN_SMITH).
+Make sure to include at least four different data types 
+(CHAR, VARCHAR2, NUMBER, DATE) for the columns and appropriate
+constraints (PK, NOT NULL, CHECK, UNIQUE). Use the DESCRIBE command 
+to verify that the columns have been defined correctly.
+
+### problem 1 commands
+
+```sql
+CREATE TABLE MICHAEL_LUNDQUIST (ID integer, firstName VARCHAR2(20) NOT NULL, lastName VARCHAR2(20) NOT NULL, addDay DATE DEFAULT SYSDATE, zip CHAR(5) NOT NULL, CONSTRAINT MICHAEL_LUNDQUIST_ID_pk PRIMARY KEY (ID));
+
+DESC MICHAEL_LUNDQUIST;
+```
+
+![problem 1](./PICS/PROBLEM_1.PNG)
+
+## problem 2
+
+Use the INSERT command to insert a new record into the table created in 
+Problem 1. When inserting a record, provide values for all columns. 
+Use the default format for the date. Use the 
+SELECT * FROM your_table_name; 
+command to display the content of the table 
+(make sure to substitute your_table_name with the actual name of your 
+table).
+
+### problem 2 commands
+
+```sql
+INSERT INTO MICHAEL_LUNDQUIST values (1, 'Michael', 'Lundquist', DEFAULT, '20194');
+```
+
+![problem 2](./PICS/PROBLEM_2.PNG)
+
+## problem 3
+
+Use the INSERT command to insert a new record into the table created in 
+Problem 1. When inserting a record, provide values for selected columns 
+only. Use the default format for the date. Use the 
+SELECT * FROM your_table_name; 
+command to display the content of the table 
+(make sure to substitute your_table_name with the actual name of your table).
+
+### problem 3 commands
+
+```sql
+INSERT INTO MICHAEL_LUNDQUIST (ID, firstName, lastName, addDay, zip) values (0, 'Michael', 'Lundquist', DEFAULT, '20194');
+```
+
+![problem 4](./PICS/PROBLEM_3.PNG)
+
+## problem 4
+
+Use the UPDATE command to update multiple values in the table created in 
+Problem 1. Use the SELECT * FROM your_table_name; 
+command to display the content of the table 
+(make sure to substitute your_table_name with the actual name of your
+table).
+
+### problem 4 commands
+
+```sql
+UPDATE MICHAEL_LUNDQUIST SET LASTNAME = 'coolGuy' where LASTNAME = 'Lundquist';
+```
+
+![problem 4](./PICS/PROBLEM_4.PNG)
+
+## problem 5
+
+Use the DELETE command to delete one specific row from the table created 
+in Problem 1. Use the 
+SELECT * FROM your_table_name;
+command to display the content of the table 
+(make sure to substitute your_table_name with the actual name of your
+table).
+
+### problem 5 commands
+
+```sql
+DELETE FROM MICHAEL_LUNDQUIST WHERE ID = 0;
+```
+
+![problem 5](./PICS/PROBLEM_5.PNG)
+
+## problem 6
+
+Use the COMMIT statement to save changes in the table created in 
+Problem 1. Use the SELECT * FROM your_table_name; command to display the 
+content of the table (make sure to substitute your_table_name with the 
+actual name of your table).
+
+### problem 6 commands
+
+```sql
+COMMIT;
+```
+
+![problem 6](./PICS/PROBLEM_6.PNG)
+
+## problem 7
+
+Use the ROLLBACK command to undo changes in the table created in Problem 1.
+What happened? Why? Use the 
+SELECT * FROM your_table_name;
+command to display the content of the table
+(make sure to substitute your_table_name with the actual name of your
+table).
+
+### problem 7 commands
+
+```sql
+ROLLBACK;
+```
+
+![problem 7](./PICS/PROBLEM_7.PNG)
+
+### Explanation
+
+The `ROLLBACK` command did nothing. It didn't delete the table itself because DDL commands can't be rolled back, only DML commands. It didn't remove any of the inserted values because they were already committed.
+
+## problem 8
+
+Use the DROP TABLE command to drop the table created in Problem 1.
+
+### problem 8 commands
+
+```sql
+DROP TABLE MICHAEL_LUNDQUIST;
+```
+
+![problem 8](./PICS/PROBLEM_8.PNG)
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practiceProblems/week3/ch8_RestrictingRows_Sorting/answers.pks

@@ -6,6 +6,9 @@ JustLee Books database. In a search condition, include one or more
 arithmetic comparison operators (=, !=, >, <, >=, etc.).
 */
 
+select table_name from user_tables;
+
+SELECT * FROM PROMOTION WHERE MINRETAIL > 20;
 
 /*
 problem2
@@ -15,6 +18,8 @@ JustLee Books database. In a search condition, include the BETWEEN … AND
 operator.
 */
 
+SELECT * FROM PROMOTION WHERE MINRETAIL BETWEEN 20 AND 30;
+
 /*
 problem3
 
@@ -22,6 +27,8 @@ Write an SQL query to retrieve records from one of the tables in the
 JustLee Books database. In a search condition, include the IN operator.
 */
 
+SELECT * FROM PROMOTION WHERE GIFT IN ('BOOK COVER', 'BOOKMARKER');
+
 /*
 problem4
 
@@ -30,6 +37,8 @@ JustLee Books database. In a search condition, include the LIKE operator
 with either % or _ (or both).
 */
 
+SELECT * FROM PROMOTION WHERE GIFT LIKE '%OO%';
+
 /*
 problem5
 
@@ -38,6 +47,8 @@ JustLee Books database. In a search condition, include the IS NULL
  operator.
 */
 
+SELECT * FROM CUSTOMERS WHERE EMAIL IS NULL;
+
 /*
 problem6
 
@@ -46,6 +57,8 @@ JustLee Books database. In a search condition, include multiple conditions
 using logical operators (AND and OR).
 */
 
+SELECT * FROM CUSTOMERS WHERE EMAIL IS NULL AND REGION = 'W';
+
 /*
 problem7
 
@@ -55,3 +68,5 @@ operators to join multiple conditions that include at least one of the
 arithmetic operators and one of the special operators. Use the
 ORDER BY statement to order the output.
 */
+
+SELECT * FROM BOOKS WHERE COST BETWEEN 10 AND 30 AND PUBID = 4 ORDER BY COST;

practiceProblems/week3/ch8_RestrictingRows_Sorting/ch8_answers.md

+# ch8, complex conditions
+
+## problem1
+
+Write an SQL query to retrieve records from one of the tables in the
+JustLee Books database. In a search condition, include one or more
+arithmetic comparison operators (=, !=, >, <, >=, etc.).
+
+```sql
+SELECT * FROM PROMOTION WHERE MINRETAIL > 20;
+```
+
+![problem 1 screenshot](./PICS/PROBLEM1.PNG)
+
+## problem2
+
+Write an SQL query to retrieve records from one of the tables in the 
+JustLee Books database. In a search condition, include the BETWEEN … AND
+operator.
+
+```sql
+SELECT * FROM PROMOTION WHERE MINRETAIL BETWEEN 20 AND 30;
+```
+
+![problem2 screenshot](./PICS/PROBLEM2.PNG)
+
+
+## problem3
+
+Write an SQL query to retrieve records from one of the tables in the
+JustLee Books database. In a search condition, include the IN operator.
+
+```SQL
+SELECT * FROM PROMOTION WHERE GIFT IN ('BOOK COVER', 'BOOKMARKER');
+```
+
+![PROBLEM3 SCREENSHOT](./PICS/PROBLEM3.PNG)
+
+
+## problem4
+
+Write an SQL query to retrieve records from one of the tables in the
+JustLee Books database. In a search condition, include the LIKE operator
+with either % or _ (or both).
+
+```SQL
+SELECT * FROM PROMOTION WHERE GIFT LIKE '%OO%';
+```
+
+![PROBLEM4 SCREENSHOT](./PICS/PROBLEM4.PNG)
+
+## problem5
+
+Write an SQL query to retrieve records from one of the tables in the
+JustLee Books database. In a search condition, include the IS NULL
+ operator.
+
+```SQL
+SELECT * FROM CUSTOMERS WHERE EMAIL IS NULL;
+```
+
+![PROBLEM5 SCREENSHOT](./PICS/PROBLEM5.PNG)
+
+## problem6
+
+Write an SQL query to retrieve records from one of the tables in the
+JustLee Books database. In a search condition, include multiple conditions
+using logical operators (AND and OR).
+
+```SQL
+SELECT * FROM CUSTOMERS WHERE EMAIL IS NULL AND REGION = 'W';
+```
+
+![PROBLEM6 SCREENSHOT](./PICS/PROBLEM6.PNG)
+
+## problem7
+
+Write a complex SQL query to retrieve records from one of the tables
+in the JustLee Books database. In a search condition, use logical
+operators to join multiple conditions that include at least one of the
+arithmetic operators and one of the special operators. Use the
+ORDER BY statement to order the output.
+
+```SQL
+SELECT * FROM BOOKS WHERE COST BETWEEN 10 AND 30 AND PUBID = 4 ORDER BY COST;
+```
+
+![PROBLEM7 SCREENSHOT](./PICS/PROBLEM7.PNG)
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