Table Column Types for Approximate Numbers

This section describes 3 types of table columns to store approximate numbers: FLOAT, REAL and DOUBLE PRECISION.

There are 3 types of table columns to store approximate numbers: FLOAT, REAL and DOUBLE PRECISION.

"FLOAT(precision)" - Approximate numeric value with specified precision or higher. No scale is specified for FLOAT.

"REAL" - Approximate numeric value with no scale. Precision is defined by the implementation.

"DOUBLE PRECISION" - Approximate numeric value with no scale. Precision is defined by the implementation and should be higher than REAL.

Examples of approximate number column types, ApproximateNumberColumns.sql:

-- ApproximateNumberColumns.sql
-- Copyright (c) 2015, HerongYang.com, All Rights Reserved.
--
CREATE TABLE ApproximateNumber (
   Line VARCHAR(8),
   X FLOAT(8), -- (precision)
   Y REAL, 
   Z DOUBLE PRECISION
   );
INSERT INTO ApproximateNumber VALUES (
   '1',
   1.11,
   2.22, 
   3.33
   );
INSERT INTO ApproximateNumber VALUES (
   '2',
   11.1111,
   22.2222, 
   33.3333
   );
INSERT INTO ApproximateNumber VALUES (
   '3',
   111.111111,
   222.222222, 
   333.333333
   );
INSERT INTO ApproximateNumber VALUES (
   '4',
   2/3,
   2/3,
   2/3
   );
SELECT * FROM ApproximateNumber;
DROP TABLE ApproximateNumber;

Output:

Line    X       Y       Z
1       1.11    2.22    3.33
2       11.1111 22.2222 33.3333
3       111.111 222.222222      333.333333
4       0.666667        0.666666666666667       0.666666666666667

Note that:

Last update: 2015.

Table of Contents

 About This Book

 Introduction of SQL

 MySQL Introduction and Installation

 Introduction of MySQL Programs

 Perl Programs and MySQL Servers

 PHP Programs and MySQL Servers

 Java Programs and MySQL Servers

 Datatypes and Data Literals

 Operations and Expressions

 Character Strings and Bit Strings

 Commonly Used Functions

Table Column Types for Different Types of Values

 Table Column Types for Character Strings

 Table Column Types for Bit Strings

 Table Column Types for Exact Numbers

Table Column Types for Approximate Numbers

 Table Column Types for Date and Time Values

 Using DDL to Create Tables and Indexes

 Using DML to Insert, Update and Delete Records

 Using SELECT to Query Database

 Transaction Management and Isolation Levels

 Locks Used in MySQL

 Defining and Calling Stored Procedures

 Variables, Loops and Cursors Used in Stored Procedures

 Outdated Tutorials

 References

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