I am performing some MySQL queries that have very large result sets. I would like to see how long they take, but I don't want all the output to be printed on my terminal because it takes up a lot of space and time. I can do this by writing a script that performs and times the query, but I was wondering if there was a way to do this directly through MySQL on the terminal. Thanks.
Change the pager in mysql like indicated here: http://www.mysqlperformanceblog.com/2013/01/21/fun-with-the-mysql-pager-command/
mysql> pager cat > /dev/null will discard the output, and mysql> pager will put it back.
Wrap your query in set #foo = (select count(*) from ( ..... ) foo)
Just run mysql console utility, then enter source file_name (where file_name contains sql commands)
Related
I'm using the Wordnet SQL database from here: http://wnsqlbuilder.sourceforge.net
It's all built fine and users with appropriate privileges have been set.
I'm trying to find synonyms of words and have tried to use the two example statements at the bottom of this page: http://wnsqlbuilder.sourceforge.net/sql-links.html
SELECT synsetid,dest.lemma,SUBSTRING(src.definition FROM 1 FOR 60) FROM wordsXsensesXsynsets AS src INNER JOIN wordsXsensesXsynsets AS dest USING(synsetid) WHERE src.lemma = 'option' AND dest.lemma <> 'option'
SELECT synsetid,lemma,SUBSTRING(definition FROM 1 FOR 60) FROM wordsXsensesXsynsets WHERE synsetid IN ( SELECT synsetid FROM wordsXsensesXsynsets WHERE lemma = 'option') AND lemma <> 'option' ORDER BY synsetid
However, they never complete. At least not in any reasonable amount of time and I have had to cancel all of the queries. All other queries seem to work find and when I break up the second SQL example, I can get the individual parts to work and complete in reasonable times (about 0.40 seconds)
When I try and run the full statement however, the MySQL command line client just hangs.
Is there a problem with this syntax? What is causing it to take so long?
EDIT:
Output of "EXPLAIN SELECT ..."
Output of "EXPLAIN EXTENDED ...; SHOW WARNINGS;"
I did more digging and looking into the various statements used and found the problem was in the IN command.
MySQL repeats the statement for every single row in the database. This is the cause of the hang, as it had to run through hundreds of thousands of records.
My remedy to this was to split the command into two separate database calls first getting the synsets, and then dynamically creating a bound SQL string to look for the words in the synsets.
For my database class the teacher assigned us to use Oracle SQL to design an application. Because I have more experience with mySQL he said I could use it instead.
I want to make my assignment look as simliar to his example as possible. What his example consists of of is one file run.sql that looks like this:
#start //this runs start.sql which creates the tables
DESC table_name; //do this for all tables
#insert //this runs insert.sql that creates dummy data
SELECT * FROM table_name; //do this for all tables
#query //this runs query.sql that runs our sample queries
#drop //this kills all the data
Is there a way to do something simliar?
Namely a way to write a query that calls external queries and outputs all data to an output.txt file?
Use 'source' to input the *.sql files
use 'create procedure' to generate the 'drop' function
use "into outfile '/file/path';" on your select to write out.
double redirect to append: "into outfile '>>/file/path';"
The source command for the mysql command-line client could do the job here:
source start.sql;
DESC table_name;
You can get more commands with help.
I'm running the mysql cmdline binary to execute queries. (Specifically, I'm executing
LOAD DATA LOCAL INFILE). I would like to have it print, after every statement, the number of records effected - but no other lines. I don't mind the line containing other info, e.g.
Query OK, 20 rows affected, 4 warnings
would be great. I can, in fact, get that - but only if I use the -v -v pair of switches, and then I get more info which I don't need, like an echo of the parsed command.
Can I do anything other than grep the output for the pattern of the line above?
It's maybe not the best solution, but you can try the SQL ROW_COUNT() function
E.g :
mysql ... -e "YOUR_QUERY;SELECT ROW_COUNT()" -B | tail -n 1
I have queries that return thousands of results, is it posible to show only query time without actual results in MySQL console or from command line?
Use SET profiling = 1; at command prompt.
Refer for more details
It's not possible to get the execution time without getting result or getting sql executed.
See why we can not get execution time without actual query execution
If you're using Linux.
Create a file query.sql
Enter the query to test into it. e.g. select * from table1
Run this command:
time mysql your_db_name -u'db_user_name' -p'your_password' < query.sql > /dev/null
The output will look something like this:
real 0m4.383s
user 0m0.022s
sys 0m0.004s
the "real" line is what you're looking at. In the above example, the query took 4.38 seconds.
Obviously, entering your DB password on the command line is not such a great idea, but will do as a quick and dirty workaround.
In PowerShell, how do I execute my mysql script so that the results are piped into a csv file? The results of this script is just a small set of columns that I would like copied into a csv file.
I can have it go directly to the shell by doing:
mysql> source myscript.sql
And I have tried various little things like:
mysql> source myscript.sql > mysql.out
mysql> source myscript.sql > mysql.csv
in infinite variation, and I just get errors. My db connections is alright because I can do basic table queries from the command line etc... I haven't been able to find a solution on the web so far either...
Any help would be really appreciated!
You seem to not be running powershell, but the mysql command line tool (perhaps you started it in a powershell console though.)
Note also that the mysql command line tool cannot export directly to csv.
However, to redirect the output to a file just run
mysql mydb < myscript.sql >mysql.out
or e.g.
echo select * from mytable | mysql mydb >mysql.out
(and whatever arguments to mysql you need, like username, hostname)
Are you looking for SELECT INTO OUTFILE ? dev.mysql.com/doc/refman/5.1/en/select.html – Pekka 19 hours ago
Yep. Select into outfile worked! But to make sure you get column names you also need to do something like:
select *
from
(
select
a,
b,
c
)
Union ALL
(Select *
from actual)