Table Column Types for Approximate Numbers

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) 1999 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:

Table of Contents

 About This Book

 Introduction of SQL

 MySQL Introduction and Installation

 Introduction of MySQL Programs

 PHP Programs and MySQL Server

 Perl 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 Byte 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

 Table Column Types for LOB (Large OBject)

 Table Column Types for Look Up Values

 Table Column Types for JSON Documents

 Table Column Types for Spatial Geometry Data

 Using DDL to Create Tables and Indexes

 Using DML to Insert, Update and Delete Records

 Using SELECT to Query Database

 Window Functions for Statistical Analysis

 Use Index for Better Performance

 Transaction Management and Isolation Levels

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 Archived Tutorials

 References

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