What are the methods of rounding in sql

SQL rounding methods include using the ROUND function, using the FLOOR and CEILING functions, using the TRUNCATE function, using the DECIMAL type and using the NUMERIC type.

#In SQL, rounding is a common numeric processing method that can preserve a numeric field to a specified number of decimal places. The following are some methods of rounding in SQL:

1. Use the ROUND function

The ROUND function is the most commonly used rounding function, which can retain a numeric field to the specified number of decimal places. The syntax of the ROUND function is as follows:

ROUND(number, decimals)

where number is the value to be rounded, and decimals is the number of decimal places to be retained. For example, to preserve a field named price to two decimal places, you would use the following SQL Statement:

SELECT ROUND(price, 2) FROM products;

2. Use the FLOOR and CEILING functions

The FLOOR function can round a value down to the nearest integer, while CEILING The function rounds a number up to the nearest integer. These two functions can also be used for rounding. For example, to preserve a field named price to two decimal places, you would use the following SQL Statement:

SELECT FLOOR(price * 100) / 100 FROM products;

or

SELECT CEILING(price * 100) / 100 FROM products;

3. Use the TRUNCATE function

The TRUNCATE function can truncate the decimal part of a numeric field and convert it to an integer . For example, to preserve a field named price to two decimal places, you would use the following SQL Statement:

SELECT TRUNCATE(price * 100) / 100 FROM products;

4. Use the DECIMAL type

In SQL, you can use the DECIMAL type to store values ​​with specified decimal places. For example, to preserve a field named price to two decimal places, you would use the following SQL Statement:

SELECT price::DECIMAL(10, 2) FROM products;

Here, ::DECIMAL(10, 2) means converting the price field to a DECIMAL type with a 10-digit integer and 2 decimal places.

5. Use the NUMERIC type

Similar to the DECIMAL type, the NUMERIC type can also be used to store values ​​with specified decimal places. However, NUMERIC types do not have DECIMAL in SQL Type commonly used. For example, to preserve a field named price to two decimal places, you can use the following SQL statement:

SELECT price::NUMERIC(10, 2) FROM products;

Here, ::NUMERIC(10, 2) means converting the price field to an integer with 10 digits and NUMERIC type with 2 decimal places.

In short, in SQL There are many methods for rounding, and you can choose the appropriate method according to your specific needs. However, when rounding, you need to pay attention to precision issues. For example, when you need to preserve a value to two decimal places, you should use ROUND function, not the FLOOR, CEILING, or TRUNCATE function.

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