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GNU LESSER GENERAL PUBLIC LICENSE ********************************* Version 2.1, February 1999 Copyright (C) 1991, 1999 Free Software Foundation, Inc. 59 Temple Place -- Suite 330, Boston, MA 02111-1307, USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. [This is the first released version of the Lesser GPL. It also counts as the successor of the GNU Library Public License, version 2, hence the version number 2.1.] Preamble ======== The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public Licenses are intended to guarantee your freedom to share and change free software--to make sure the software is free for all its users. This license, the Lesser General Public License, applies to some specially designated software--typically libraries--of the Free Software Foundation and other authors who decide to use it. 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See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA. Also add information on how to contact you by electronic and paper mail. You should also get your employer (if you work as a programmer) or your school, if any, to sign a "copyright disclaimer" for the library, if necessary. Here is a sample; alter the names: Yoyodyne, Inc., hereby disclaims all copyright interest in the library `Frob' (a library for tweaking knobs) written by James Random Hacker. SIGNATURE OF TY COON, 1 April 1990 Ty Coon, President of Vice That's all there is to it! Pieces of the manual in transit ******************************* * Menu: * Installing binary:: Installing a MySQL Binary Distribution * Perl support:: Perl Installation Comments * Group by functions:: Functions for Use with `GROUP BY' Clauses Installing a MySQL Binary Distribution ====================================== * Menu: * Linux-RPM:: Linux RPM files * Building clients:: Building client programs You need the following tools to install a MySQL binary distribution: * GNU `gunzip' to uncompress the distribution. * A reasonable `tar' to unpack the distribution. GNU `tar' is known to work. Sun `tar' is known to have problems. An alternative installation method under Linux is to use RPM (RedHat Package Manager) distributions. *Note Linux-RPM::. If you run into problems, *PLEASE ALWAYS USE* `mysqlbug' when posting questions to <mysql@lists.mysql.com>. Even if the problem isn't a bug, `mysqlbug' gathers system information that will help others solve your problem. By not using `mysqlbug', you lessen the likelihood of getting a solution to your problem! You will find `mysqlbug' in the `bin' directory after you unpack the distribution. *Note Bug reports::. The basic commands you must execute to install and use a MySQL binary distribution are: shell> groupadd mysql shell> useradd -g mysql mysql shell> cd /usr/local shell> gunzip < /path/to/mysql-VERSION-OS.tar.gz | tar xvf - shell> ln -s mysql-VERSION-OS mysql shell> cd mysql shell> scripts/mysql_install_db shell> chown -R root /usr/local/mysql shell> chown -R mysql /usr/local/mysql/data shell> chgrp -R mysql /usr/local/mysql shell> chown -R root /usr/local/mysql/bin shell> bin/safe_mysqld --user=mysql & You can add new users using the `bin/mysql_setpermission' script if you install the `DBI' and `Msql-Mysql-modules' Perl modules. A more detailed description follows. To install a binary distribution, follow the steps below, then proceed to *Note Post-installation::, for post-installation setup and testing: 1. Pick the directory under which you want to unpack the distribution, and move into it. In the example below, we unpack the distribution under `/usr/local' and create a directory `/usr/local/mysql' into which MySQL is installed. (The following instructions therefore assume you have permission to create files in `/usr/local'. If that directory is protected, you will need to perform the installation as `root'.) 2. Obtain a distribution file from one of the sites listed in *Note Getting MySQL: Getting MySQL. MySQL binary distributions are provided as compressed `tar' archives and have names like `mysql-VERSION-OS.tar.gz', where `VERSION' is a number (for example, `3.21.15'), and `OS' indicates the type of operating system for which the distribution is intended (for example, `pc-linux-gnu-i586'). 3. If you see a binary distribution marked with the `-max' prefix, this means that the binary has support for transaction-safe tables and other features. *Note `mysqld-max': mysqld-max. Note that all binaries are built from the same MySQL source distribution. 4. Add a user and group for `mysqld' to run as: shell> groupadd mysql shell> useradd -g mysql mysql These commands add the `mysql' group and the `mysql' user. The syntax for `useradd' and `groupadd' may differ slightly on different versions of Unix. They may also be called `adduser' and `addgroup'. You may wish to call the user and group something else instead of `mysql'. 5. Change into the intended installation directory: shell> cd /usr/local 6. Unpack the distribution and create the installation directory: shell> gunzip < /path/to/mysql-VERSION-OS.tar.gz | tar xvf - shell> ln -s mysql-VERSION-OS mysql The first command creates a directory named `mysql-VERSION-OS'. The second command makes a symbolic link to that directory. This lets you refer more easily to the installation directory as `/usr/local/mysql'. 7. Change into the installation directory: shell> cd mysql You will find several files and subdirectories in the `mysql' directory. The most important for installation purposes are the `bin' and `scripts' subdirectories. `bin' This directory contains client programs and the server You should add the full pathname of this directory to your `PATH' environment variable so that your shell finds the MySQL programs properly. *Note Environment variables::. `scripts' This directory contains the `mysql_install_db' script used to initialize the `mysql' database containing the grant tables that store the server access permissions. 8. If you would like to use `mysqlaccess' and have the MySQL distribution in some non-standard place, you must change the location where `mysqlaccess' expects to find the `mysql' client. Edit the `bin/mysqlaccess' script at approximately line 18. Search for a line that looks like this: $MYSQL = '/usr/local/bin/mysql'; # path to mysql executable Change the path to reflect the location where `mysql' actually is stored on your system. If you do not do this, you will get a `Broken pipe' error when you run `mysqlaccess'. 9. Create the MySQL grant tables (necessary only if you haven't installed MySQL before): shell> scripts/mysql_install_db Note that MySQL versions older than Version 3.22.10 started the MySQL server when you run `mysql_install_db'. This is no longer true! 10. Change ownership of binaries to `root' and ownership of the data directory to the user that you will run `mysqld' as: shell> chown -R root /usr/local/mysql shell> chown -R mysql /usr/local/mysql/data shell> chgrp -R mysql /usr/local/mysql The first command changes the `owner' attribute of the files to the `root' user, the second one changes the `owner' attribute of the data directory to the `mysql' user, and the third one changes the `group' attribute to the `mysql' group. 11. If you want to install support for the Perl `DBI'/`DBD' interface, see *Note Perl support::. 12. If you would like MySQL to start automatically when you boot your machine, you can copy `support-files/mysql.server' to the location where your system has its startup files. More information can be found in the `support-files/mysql.server' script itself and in *Note Automatic start::. After everything has been unpacked and installed, you should initialize and test your distribution. You can start the MySQL server with the following command: shell> bin/safe_mysqld --user=mysql & *Note `safe_mysqld': safe_mysqld. *Note Post-installation::. Perl Installation Comments ========================== * Menu: * Perl installation:: Installing Perl on Unix * ActiveState Perl:: Installing ActiveState Perl on Windows * Windows Perl:: Installing the MySQL Perl distribution on Windows * Perl support problems:: Problems using the Perl `DBI'/`DBD' interface Installing Perl on Unix ----------------------- Perl support for MySQL is provided by means of the `DBI'/`DBD' client interface. *Note Perl::. The Perl `DBD'/`DBI' client code requires Perl Version 5.004 or later. The interface *will not work* if you have an older version of Perl. MySQL Perl support also requires that you've installed MySQL client programming support. If you installed MySQL from RPM files, client programs are in the client RPM, but client programming support is in the developer RPM. Make sure you've installed the latter RPM. As of Version 3.22.8, Perl support is distributed separately from the main MySQL distribution. If you want to install Perl support, the files you will need can be obtained from `http://www.mysql.com/Downloads/Contrib/'. The Perl distributions are provided as compressed `tar' archives and have names like `MODULE-VERSION.tar.gz', where `MODULE' is the module name and `VERSION' is the version number. You should get the `Data-Dumper', `DBI', and `Msql-Mysql-modules' distributions and install them in that order. The installation procedure is shown below. The example shown is for the `Data-Dumper' module, but the procedure is the same for all three distributions: 1. Unpack the distribution into the current directory: shell> gunzip < Data-Dumper-VERSION.tar.gz | tar xvf - This command creates a directory named `Data-Dumper-VERSION'. 2. Change into the top-level directory of the unpacked distribution: shell> cd Data-Dumper-VERSION 3. Build the distribution and compile everything: shell> perl Makefile.PL shell> make shell> make test shell> make install The `make test' command is important because it verifies that the module is working. Note that when you run that command during the `Msql-Mysql-modules' installation to exercise the interface code, the MySQL server must be running or the test will fail. It is a good idea to rebuild and reinstall the `Msql-Mysql-modules' distribution whenever you install a new release of MySQL, particularly if you notice symptoms such as all your `DBI' scripts dumping core after you upgrade MySQL. If you don't have the right to install Perl modules in the system directory or if you to install local Perl modules, the following reference may help you: `http://www.iserver.com/support/contrib/perl5/modules.html' Look under the heading `Installing New Modules that Require Locally Installed Modules'. Installing ActiveState Perl on Windows -------------------------------------- To install the MySQL `DBD' module with ActiveState Perl on Windows, you should do the following: * Get ActiveState Perl from `http://www.activestate.com/Products/ActivePerl/index.html' and install it. * Open a DOS shell. * If required, set the HTTP_proxy variable. For example, you might try: set HTTP_proxy=my.proxy.com:3128 * Start the PPM program: C:\> c:\perl\bin\ppm.pl * If you have not already done so, install `DBI': ppm> install DBI * If this succeeds, run the following command: install ftp://ftp.de.uu.net/pub/CPAN/authors/id/JWIED/DBD-mysql-1.2212.x86.ppd The above should work at least with ActiveState Perl Version 5.6. If you can't get the above to work, you should instead install the *MyODBC* driver and connect to MySQL server through ODBC: use DBI; $dbh= DBI->connect("DBI:ODBC:$dsn","$user","$password") || die "Got error $DBI::errstr when connecting to $dsn\n"; Installing the MySQL Perl Distribution on Windows ------------------------------------------------- The MySQL Perl distribution contains `DBI', `DBD:MySQL' and `DBD:ODBC'. * Get the Perl distribution for Windows from `http://www.mysql.com/download.html'. * Unzip the distribution in `C:' so that you get a `C:\PERL' directory. * Add the directory `C:\PERL\BIN' to your path. * Add the directory `C:\PERL\BIN\MSWIN32-x86-thread' or `C:\PERL\BIN\MSWIN32-x86' to your path. * Test that `perl' works by executing `perl -v' in a DOS shell. Problems Using the Perl `DBI'/`DBD' Interface --------------------------------------------- If Perl reports that it can't find the `../mysql/mysql.so' module, then the problem is probably that Perl can't locate the shared library `libmysqlclient.so'. You can fix this by any of the following methods: * Compile the `Msql-Mysql-modules' distribution with `perl Makefile.PL -static -config' rather than `perl Makefile.PL'. * Copy `libmysqlclient.so' to the directory where your other shared libraries are located (probably `/usr/lib' or `/lib'). * On Linux you can add the pathname of the directory where `libmysqlclient.so' is located to the `/etc/ld.so.conf' file. * Add the pathname of the directory where `libmysqlclient.so' is located to the `LD_RUN_PATH' environment variable. If you get the following errors from `DBD-mysql', you are probably using `gcc' (or using an old binary compiled with `gcc'): /usr/bin/perl: can't resolve symbol '__moddi3' /usr/bin/perl: can't resolve symbol '__divdi3' Add `-L/usr/lib/gcc-lib/... -lgcc' to the link command when the `mysql.so' library gets built (check the output from `make' for `mysql.so' when you compile the Perl client). The `-L' option should specify the pathname of the directory where `libgcc.a' is located on your system. Another cause of this problem may be that Perl and MySQL aren't both compiled with `gcc'. In this case, you can solve the mismatch by compiling both with `gcc'. If you get the following error from `Msql-Mysql-modules' when you run the tests: t/00base............install_driver(mysql) failed: Can't load '../blib/arch/auto/DBD/mysql/mysql.so' for module DBD::mysql: ../blib/arch/auto/DBD/mysql/mysql.so: undefined symbol: uncompress at /usr/lib/perl5/5.00503/i586-linux/DynaLoader.pm line 169. it means that you need to include the compression library, -lz, to the link line. This can be doing the following change in the file `lib/DBD/mysql/Install.pm': $sysliblist .= " -lm"; to $sysliblist .= " -lm -lz"; After this, you MUST run 'make realclean' and then proceed with the installation from the beginning. If you want to use the Perl module on a system that doesn't support dynamic linking (like SCO) you can generate a static version of Perl that includes `DBI' and `DBD-mysql'. The way this works is that you generate a version of Perl with the `DBI' code linked in and install it on top of your current Perl. Then you use that to build a version of Perl that additionally has the `DBD' code linked in, and install that. On SCO, you must have the following environment variables set: shell> LD_LIBRARY_PATH=/lib:/usr/lib:/usr/local/lib:/usr/progressive/lib or shell> LD_LIBRARY_PATH=/usr/lib:/lib:/usr/local/lib:/usr/ccs/lib:/usr/progressive/lib:/usr/skunk/lib shell> LIBPATH=/usr/lib:/lib:/usr/local/lib:/usr/ccs/lib:/usr/progressive/lib:/usr/skunk/lib shell> MANPATH=scohelp:/usr/man:/usr/local1/man:/usr/local/man:/usr/skunk/man: First, create a Perl that includes a statically linked `DBI' by running these commands in the directory where your `DBI' distribution is located: shell> perl Makefile.PL -static -config shell> make shell> make install shell> make perl Then you must install the new Perl. The output of `make perl' will indicate the exact `make' command you will need to execute to perform the installation. On SCO, this is `make -f Makefile.aperl inst_perl MAP_TARGET=perl'. Next, use the just-created Perl to create another Perl that also includes a statically-linked `DBD::mysql' by running these commands in the directory where your `Msql-Mysql-modules' distribution is located: shell> perl Makefile.PL -static -config shell> make shell> make install shell> make perl Finally, you should install this new Perl. Again, the output of `make perl' indicates the command to use. Functions for Use with `GROUP BY' Clauses ========================================= If you use a group function in a statement containing no `GROUP BY' clause, it is equivalent to grouping on all rows. `COUNT(expr)' Returns a count of the number of non-`NULL' values in the rows retrieved by a `SELECT' statement: mysql> select student.student_name,COUNT(*) from student,course where student.student_id=course.student_id GROUP BY student_name; `COUNT(*)' is somewhat different in that it returns a count of the number of rows retrieved, whether or not they contain `NULL' values. `COUNT(*)' is optimized to return very quickly if the `SELECT' retrieves from one table, no other columns are retrieved, and there is no `WHERE' clause. For example: mysql> select COUNT(*) from student; `COUNT(DISTINCT expr,[expr...])' Returns a count of the number of different non-`NULL' values: mysql> select COUNT(DISTINCT results) from student; In MySQL you can get the number of distinct expression combinations that don't contain NULL by giving a list of expressions. In ANSI SQL you would have to do a concatenation of all expressions inside `CODE(DISTINCT ..)'. `AVG(expr)' Returns the average value of `expr': mysql> select student_name, AVG(test_score) from student GROUP BY student_name; `MIN(expr)' `MAX(expr)' Returns the minimum or maximum value of `expr'. `MIN()' and `MAX()' may take a string argument; in such cases they return the minimum or maximum string value. *Note MySQL indexes::. mysql> select student_name, MIN(test_score), MAX(test_score) from student GROUP BY student_name; `SUM(expr)' Returns the sum of `expr'. Note that if the return set has no rows, it returns NULL! `STD(expr)' `STDDEV(expr)' Returns the standard deviation of `expr'. This is an extension to ANSI SQL. The `STDDEV()' form of this function is provided for Oracle compatibility. `BIT_OR(expr)' Returns the bitwise `OR' of all bits in `expr'. The calculation is performed with 64-bit (`BIGINT') precision. `BIT_AND(expr)' Returns the bitwise `AND' of all bits in `expr'. The calculation is performed with 64-bit (`BIGINT') precision. MySQL has extended the use of `GROUP BY'. You can use columns or calculations in the `SELECT' expressions that don't appear in the `GROUP BY' part. This stands for _any possible value for this group_. You can use this to get better performance by avoiding sorting and grouping on unnecessary items. For example, you don't need to group on `customer.name' in the following query: mysql> select order.custid,customer.name,max(payments) from order,customer where order.custid = customer.custid GROUP BY order.custid; In ANSI SQL, you would have to add `customer.name' to the `GROUP BY' clause. In MySQL, the name is redundant if you don't run in ANSI mode. *Don't use this feature* if the columns you omit from the `GROUP BY' part aren't unique in the group! You will get unpredictable results. In some cases, you can use `MIN()' and `MAX()' to obtain a specific column value even if it isn't unique. The following gives the value of `column' from the row containing the smallest value in the `sort' column: substr(MIN(concat(rpad(sort,6,' '),column)),7) *Note example-Maximum-column-group-row::. Note that if you are using MySQL Version 3.22 (or earlier) or if you are trying to follow ANSI SQL, you can't use expressions in `GROUP BY' or `ORDER BY' clauses. You can work around this limitation by using an alias for the expression: mysql> SELECT id,FLOOR(value/100) AS val FROM tbl_name GROUP BY id,val ORDER BY val; In MySQL Version 3.23 you can do: mysql> SELECT id,FLOOR(value/100) FROM tbl_name ORDER BY RAND();