3.5. Using mysql in Batch Mode
In the previous sections, you used mysql
interactively to enter queries and view the results. You can also
run mysql in batch mode. To do this, put the
commands you want to run in a file, then tell
mysql to read its input from the file:
shell> mysql < batch-file
If you are running mysql under Windows and have
some special characters in the file that cause problems, you can
do this:
C:\> mysql -e "source batch-file"
If you need to specify connection parameters on the command line,
the command might look like this:
shell> mysql -h host -u user -p < batch-file
Enter password: ********
When you use mysql this way, you are creating a
script file, then executing the script.
If you want the script to continue even if some of the statements
in it produce errors, you should use the --force
command-line option.
Why use a script? Here are a few reasons:
If you run a query repeatedly (say, every day or every week),
making it a script allows you to avoid retyping it each time
you execute it.
You can generate new queries from existing ones that are
similar by copying and editing script files.
Batch mode can also be useful while you're developing a query,
particularly for multiple-line commands or multiple-statement
sequences of commands. If you make a mistake, you don't have
to retype everything. Just edit your script to correct the
error, then tell mysql to execute it again.
-
If you have a query that produces a lot of output, you can run
the output through a pager rather than watching it scroll off
the top of your screen:
shell> mysql < batch-file | more
-
You can catch the output in a file for further processing:
shell> mysql < batch-file > mysql.out
You can distribute your script to other people so that they
can also run the commands.
Some situations do not allow for interactive use, for example,
when you run a query from a cron job. In
this case, you must use batch mode.
The default output format is different (more concise) when you run
mysql in batch mode than when you use it
interactively. For example, the output of SELECT DISTINCT
species FROM pet looks like this when
mysql is run interactively:
+---------+
| species |
+---------+
| bird |
| cat |
| dog |
| hamster |
| snake |
+---------+
In batch mode, the output looks like this instead:
species
bird
cat
dog
hamster
snake
If you want to get the interactive output format in batch mode,
use mysql -t. To echo to the output the
commands that are executed, use mysql -vvv.
You can also use scripts from the mysql prompt
by using the source or \.
command:
mysql> source filename;
mysql> \. filename
