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Compare size of decimal data type in mysql database

Popularity：454 ℃/2024-08-15 21:44:14

In MySQL.DECIMALThe data type is used to store exact values, which is ideal for scenarios that require high-precision calculations, such as financial applications. When we need to compare the values in a MySQL database with theDECIMALWhen the size of the type data is small, you can use standard comparison operators such as>, <, >=, <=, = cap (a poem)<>(or!=）。

The following is a detailed example of how to use the MySQLDECIMALdata types and compare their sizes.

Step 1: Create a Table

First, we create a file containing theDECIMALA table of type columns.

CREATE TABLE products (  
    id INT AUTO_INCREMENT PRIMARY KEY,  
    name VARCHAR(255) NOT NULL,  
    price DECIMAL(10, 2) NOT NULL  
);

In this example, we have created a file namedproductstable that contains aDECIMALtypedpricecolumn for storing product prices.DECIMAL(10, 2)Indicates that there can be a total of 10 digits, 2 of which are decimals.

Step 2: Insert data

Next, we insert some data into the table.

INSERT INTO products (name, price) VALUES ('Product A', 19.99);  
INSERT INTO products (name, price) VALUES ('Product B', 29.99);  
INSERT INTO products (name, price) VALUES ('Product C', 15.99);

Step 3: Query and compare data

Now, we can use a SQL query to compare theDECIMALThe size of the type data.

Example 1: Finding products with a price higher than 20

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SELECT * FROM products WHERE price > 20.00;.

Example 2: Finding the lowest priced product

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SELECT * FROM products ORDER BY price ASC LIMIT 1;

Example 3: Finding products with prices between 10 and 20

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SELECT * FROM products WHERE price BETWEEN 10.00 AND 20.00;

Full Sample Code

Combining the above steps, you can use the following complete SQL script to create tables, insert data, and execute some queries.

-- Create Table
CREATE TABLE products (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(255) NOT NULL,
    price DECIMAL(10, 2) NOT NULL
);
  
-- insert data
INSERT INTO products (name, price) VALUES ('Product A', 19.99);
INSERT INTO products (name, price) VALUES ('Product B', 29.99);
INSERT INTO products (name, price) VALUES ('Product C', 15.99);
  
-- Check prices above20any product
SELECT * FROM products WHERE price > 20.00;
  
-- 查询价格最低any product
SELECT * FROM products ORDER BY price ASC LIMIT 1;
  
-- Check price at10until (a time)20之间any product
SELECT * FROM products WHERE price BETWEEN 10.00 AND 20.00;

This example demonstrates how to use theDECIMALdata types and compares the magnitude of these values with standard SQL queries. This is useful for working with financial data that requires high precision calculations or any other scenario that requires precise numerical comparisons.

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