Operations and Functions for Character Strings

Describes operations and functions for character strings, sequences of characters from predefined character sets.

A character string is a sequence of characters chosen from a predefined character set. There are three types of character sets:

Operations involving character strings are:

Examples of character strings, CharStringOps.sql:

-- CharStringOps.sql
-- Copyright (c) 1999 HerongYang.com. All Rights Reserved.
--
SELECT 'abc';
SELECT CONCAT('abc','xyz'); -- MySQL do not support || as concatenation
SELECT UPPER('fortran');
SELECT SUBSTRING('Hello world!',7,5); -- Starting position is 1
SELECT TRIM('   011.99000 '); -- Trimming ' ' on both ends
SELECT TRIM(BOTH ' ' FROM '   011.99000 ');
SELECT TRIM(LEADING '0' FROM '011.99000');
SELECT TRIM(TRAILING '0' FROM '011.99000');
SELECT CHAR_LENGTH('Hello world!');
SELECT 'abc' > 'xyz';
SELECT 'abc' < 'xyz';
SELECT 'abc ' < 'xyz'; -- Extra characters are ignored
SELECT 'abc ' = 'abc'; -- Extra characters are ignored
SELECT 'abc ' = 'ABC'; -- Case ignored
SELECT POSITION('world' IN 'Hello world!');
SELECT 'Montreal' LIKE 'M_nt%'; -- '_': any char; '%': any string

Run CharStringOps.sql, you will get:

herong> %mysql%\bin\mysql --user=root --password=TopSecret \
   < CharStringOps.sql

abc
abc
CONCAT('abc','xyz')
abcxyz
UPPER('fortran')
FORTRAN
SUBSTRING('Hello world!',7,5)
world
TRIM('   011.99000 ')
011.99000
TRIM(BOTH ' ' FROM '   011.99000 ')
011.99000
TRIM(LEADING '0' FROM '011.99000')
11.99000
TRIM(TRAILING '0' FROM '011.99000')
011.99
CHAR_LENGTH('Hello world!')
12
'abc' > 'xyz'
0
'abc' < 'xyz'
1
'abc ' < 'xyz'
1
'abc ' = 'abc'
1
'abc ' = 'ABC'
1
POSITION('world' IN 'Hello world!')
7
'Montreal' LIKE 'M_nt%'
1

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

Operations and Functions for Character Strings

 Operations and Functions for Bit Strings

 Commonly Used Functions

 Table Column Types for Different Types of Values

 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

 Locks Used in MySQL

 Defining and Calling Stored Procedures

 Variables, Loops and Cursors Used in Stored Procedures

 System, User-Defined and Stored Procedure Variables

 MySQL Server Administration

 Storage Engines in MySQL Server

 InnoDB Storage Engine - Primary and Secondary Indexes

 Performance Tuning and Optimization

 Bulk Changes on Large Tables

 MySQL Server on macOS

 Installing MySQL Server on Linux

 Connection, Performance and Second Instance on Linux

 Archived Tutorials

 References

 Full Version in PDF/EPUB