Dyntex.net Support Centre: MySQL Reference Manual p.453

<< previous page -- table of contents -- next page >>

Chapter_1

Chapter_2

Chapter_3

Chapter_4

Chapter_5

Return to Table of Contents

Table of Contents
1. General Information
2. MySQL Installation
3. Tutorial Introduction
4. Database Administration
5. MySQL Optimisation
6. MySQL Language Reference
7. MySQL Table Types
8. MySQL APIs
9. Extending MySQL

Chapter 6: MySQL Language Reference 453 to use only one of the specied indexes to nd rows in the table. The alternative syntax IGNORE INDEX (key_list) can be used to tell MySQL to not use some particular index. USE/IGNORE KEY are synonyms for USE/IGNORE INDEX. Some examples: mysql> SELECT * FROM table1,table2 WHERE table1.id=table2.id; mysql> SELECT * FROM table1 LEFT JOIN table2 ON table1.id=table2.id; mysql> SELECT * FROM table1 LEFT JOIN table2 USING (id); mysql> SELECT * FROM table1 LEFT JOIN table2 ON table1.id=table2.id -> LEFT JOIN table3 ON table2.id=table3.id; mysql> SELECT * FROM table1 USE INDEX (key1,key2) -> WHERE key1=1 AND key2=2 AND key3=3; mysql> SELECT * FROM table1 IGNORE INDEX (key3) -> WHERE key1=1 AND key2=2 AND key3=3; See Section 5.2.6 [LEFT JOIN optimisation], page 346. 6.4.1.2 UNION Syntax SELECT ... UNION [ALL] SELECT ... [UNION SELECT ...] UNION is implemented in MySQL 4.0.0. UNION is used to combine the result from many SELECT statements into one result set. The columns listed in the select expression portion of the SELECT should have the same type. The column names used in the rst SELECT query will be used as the column names for the results returned. The SELECT commands are normal select commands, but with the following restrictions: Only the last SELECT command can have INTO OUTFILE. If you don't use the keyword ALL for the UNION, all returned rows will be unique, as if you had done a DISTINCT for the total result set. If you specify ALL, then you will get all matching rows from all the used SELECT statements. If you want to use an ORDER BY for the total UNION result, you should use parentheses: (SELECT a FROM table_name WHERE a=10 AND B=1 ORDER BY a LIMIT 10) UNION (SELECT a FROM table_name WHERE a=11 AND B=2 ORDER BY a LIMIT 10) ORDER BY a; 6.4.2 HANDLER Syntax HANDLER tbl_name OPEN [ AS alias ] HANDLER tbl_name READ index_name { = | >= | <= | < } (value1,value2,...) [ WHERE ... ] [LIMIT ... ]

MySQL Reference Manual

Our Partners

SpiritHost - web hosting for spiritual and education sites
SpiritHit.com - Religious and Spiritual Portal

Return to Table of Contents	Back to top

Web Hosting: Manuals & FAQ's

1. Unix-Based Web Hosting
2. Unix Dedicated Servers
3. Windows Dedicated Servers
4. CuteFTP User’s Guide
5. CuteHTML User’s Guide
6. WS_FTP Pro User's Guide
7. Miva Order User's Guide
8. Miva Merchant User's Guide