Bool

Overview

A BOOL is a data type mainly used for expressions that will return only two possible values, true and false.

Bool is stored as a bitmap in u64 values.

BOOLEAN is an alias for the BOOL data type. You can create a table using BOOLEAN. However, it will be stored and processed equivalently to BOOL.

Format

• FALSE
• TRUE

Examples

Below are a few examples of using a bool data type:

Case #1: Create a Table

A librarian will create a borrowBook table that he will use to store book borrowing data. The table comprises the borrowed ID, the book name, the borrower, and the book’s returned status, which uses the bool data type.

CREATE TABLE borrowBook  (  
   borrowID INT, 
   bookName TEXT,
   borrower TEXT,
   returnedStat BOOL NOT NULL  
);  
INSERT INTO borrowBook (borrowID,bookName, borrower, returnedStat)  
VALUES  
    (101, 'The Silent Patient', 'Mike', TRUE),  
    (201, 'Malibu Rising', 'Jean', TRUE),  
    (301, 'The Guest List', 'Mark', FALSE),  
    (401, 'The Four Winds', 'Cliff', TRUE),  
    (501, 'The Vanishing Half: A Novel', 'Sarah', TRUE),  
    (601, 'Red, White & Royal Blue', 'Anna', FALSE),  
    (701, 'The Duke and I', 'Blake', FALSE),  
    (801, 'The Lord of the Rings', 'Sandra', FALSE);  

The borrowBook table has been successfully created after executing the above query:

COMPLETE
INSERT 0 8

Case #2: Display the Table

Run the SELECT statement to get all records from the borrowBook table:

SELECT * FROM borrowBook;

It will return the result as displayed below:

+-----------+---------------------------------+------------+---------------+
| borrowid  | bookname                        | borrower   | returnedstat  |
+-----------+---------------------------------+------------+---------------+
| 101       | The Silent Patient              | Mike       | t             |
| 201       | Malibu Rising                   | Jean       | t             |
| 301       | The Guest List                  | Mark       | f             |
| 401       | The Four Winds                  | Cliff      | t             |
| 501       | The Vanishing Half: A Novel     | Sarah      | t             |
| 601       | Red, White & Royal Blue         | Anna       | f             |
| 701       | The Duke and I                  | Blake      | f             |
| 801       | The Lord of the Rings           | Sandra     | f             |
+-----------+---------------------------------+------------+---------------+

Case #3: List of the Returned Books

In the below example, the following statement is used to retrieve all the books that have already been returned:

SELECT * FROM borrowbook       
WHERE returnedstat= 'true';

We will get the following results:

+-----------+---------------------------------+------------+---------------+
| borrowid  | bookname                        | borrower   | returnedstat  |
+-----------+---------------------------------+------------+---------------+
| 101       | The Silent Patient              | Mike       | t             |
| 201       | Malibu Rising                   | Jean       | t             |
| 401       | The Four Winds                  | Cliff      | t             |
| 501       | The Vanishing Half: A Novel     | Sarah      | t             |
+-----------+---------------------------------+------------+---------------+

Case #4: List of the Unreturned Books

Now, we will acquire all of the book records that haven’t been returned yet by running the SELECT statement with a specified WHERE condition as false:

SELECT * FROM borrowbook       
WHERE returnedstat= 'false'; 

We will get the following results:

+-----------+---------------------------------+------------+---------------+
| borrowid  | bookname                        | borrower   | returnedstat  |
+-----------+---------------------------------+------------+---------------+
| 301       | The Guest List                  | Mark       | f             |
| 601       | Red, White & Royal Blue         | Anna       | f             |
| 701       | The Duke and I                  | Blake      | f             |
| 801       | The Lord of the Rings           | Sandra     | f             |
+-----------+---------------------------------+------------+---------------+

Case #5: Check a Book’s Return Status

In this example, we are going to figure out the returned status of the book “The Lord of the Rings” by executing the SELECT statement with a specified column in the WHERE clause:

SELECT * FROM borrowbook  
WHERE bookname = 'The Lord of the Rings';

The above query will filter all records based on the specified conditions, and we know that Sandra hasn’t returned the book yet:

+-----------+---------------------------------+------------+---------------+
| borrowid  | bookname                        | borrower   | returnedstat  |
+-----------+---------------------------------+------------+---------------+
| 801       | The Lord of the Rings           | Sandra     | f             |
+-----------+---------------------------------+------------+---------------+