Activity: SQL basics

(no submission)

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Purpose:

• Be familiar with database queries
• Practice writing and interpreting SQL
• Verify that you have access to the database server and the database server works properly
• Get ready to work on homework assignment and course project

You may make a copy of a activity-sql-basic.sql and complete this activity or type your queries directly in your database environment and export the .sql file later.

You may work alone or with 2-3 other students in this course (max size=4).

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Let's warm up

1. Create a table

   CREATE TABLE my_todo
          (id INT,
          task VARCHAR(20) NOT NULL,
          priority VARCHAR(10) DEFAULT 'normal',
          PRIMARY KEY (id));   

2. Insert data into a table

   INSERT INTO my_todo VALUES (99, "read book", "low");
   INSERT INTO my_todo VALUES (101, 'do homework 2', "normal");
   INSERT INTO my_todo VALUES (212, "write sql", "high");     
   INSERT INTO my_todo VALUES (114, "practice", "normal");
   INSERT INTO my_todo (id, task) VALUES (301, "practice");
   INSERT INTO my_todo (task, id) VALUES ("practice", 302);
   INSERT INTO my_todo (task, priority, id) VALUES ("practice", 'normal', 303);     
   

   Thought question: 
   What would happen if we ran the following command? 
   
   INSERT INTO my_todo VALUES (301, "practice");    -- given priority has the default value 
   

3. Retrieve data

   SELECT * FROM my_todo;

   SELECT * FROM my_todo WHERE priority="high";

   SELECT * FROM my_todo WHERE priority='normal';

   SELECT task FROM my_todo WHERE priority="normal";

   SELECT * FROM my_todo WHERE task LIKE "%sql" OR priority = "low";

   SELECT DISTINCT * FROM my_todo;

   SELECT DISTINCT priority, task FROM my_todo;

   SELECT DISTINCT priority FROM my_todo;

4. Update data

   UPDATE my_todo SET priority="low";

   UPDATE my_todo SET priority="high" where task="write sql";

   UPDATE my_todo SET priority="normal" where task="do homework 2";

5. Delete data

   DELETE FROM my_todo WHERE task="do homework 2";

   DELETE FROM my_todo;

6. Drop a table

   DROP TABLE my_todo;

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Import alldbs.sql into your database server. Write SQL queries to solve the following problems. You will need to consider tables:  loan,  depositor,  borrower,  and  account. (Sample data of these tables are also included at the end of this activity for your convenience)

1. Find all loans over $1200
   
2. Find the loan number for each loan of an amount greater than $1200
   
3. Which branches have loan amounts greater than $1200?
   
4. List the branches that have loan amounts greater than $1200 in alphabetical order
   
5. I need the account numbers and balances of all our customers
   
6. Suppose the bank is updating the customers' account balances with 2.5% interest; that is, if the customer currently has $100 in his/her account, the balance will be updated to $100 * 1.025 = $102.5. Display account numbers and the balances with 2.5% interest of all customers. Also, rename the column header for balances as "New Balance"
   
7. Display the names of our customers, the branches they have accounts, and the amounts they have in their accounts. List them by the branches and then the amounts
   
8. Show me a list of customer names and the amounts they borrowed
   
9. Give me the names of all customers who have a loan at the Perryridge branch
   
10. Find the names of all customers, their loan numbers, the branch they have their loan with, and the amount of their loan. Note: do not list the common column(s) twice
    
11. [optional] Find the names of all customers who have a loan, an account, or both from the bank
    
12. [optional] Find the names of all customers who have a loan and an account from the bank
    

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Copyright © 2026 Upsorn Praphamontripong
Released under the CC-BY-NC-SA 4.0 license.
Last updated 2026-02-08 10:43