How to append data from SQL to an existing file - mysql

SQL has the option to dump data into a file, using the INTO OUTFILE option, for exmaple
SELECT * from FIshReport INTO OUTFILE './FishyFile'
The problem is, this command is only allowed if the file didn't exist before it. It creates the file and then enters the data.
So, is there any way to append data to a file this way?

As the MySQL page on SELECT syntax suggests:
http://dev.mysql.com/doc/refman/5.0/en/select.html
the alternative to this is to issue the SELECT from the MySQL client:
However, if the MySQL client software is installed on the remote machine,
you can instead use a client command such as mysql -e "SELECT ..." > file_name
to generate the file on the client host.
which, in your case, would be modified to be:
mysql -e "SELECT * from FishReport" >> file_name
so that you simply append to the file.
From your Tcl script, you could simply issue this as an exec command:
http://www.tcl.tk/man/tcl/tutorial/Tcl26.html

I think MySQL does not allow appending data to an existing file or overwriting an existing file for security reasons.
A work around could be to save resuts in seperate files and then append the using file IO.

You could always append the output from your SQL script to a file using >>
For example (for Sybase):
isql < script.sql >> outputfile.out
I can't tell you what the equivalent is for MySQL but the principle should be the same.
Of course output will all go to one file so if your SQL script is outputting various SQL selects to different output files then you'd need to split the script up.

You could just add it to a variable. Then use a SELECT with UNION.
declare t varchar(100);
set #myvar = concat('
select * INTO OUTFILE \'',file,'\'
from (
select \'',t,'\'
union all
SELECT col from tbl where x
) a'
);
PREPARE stmt1 FROM #myvar;
EXECUTE stmt1;
Deallocate prepare stmt1;

Related

Executing sql strings from csv into mysql database

I've created a huge .csv with only one column, each column is a valid sql string update like:
UPDATE TBL SET LAST = 0 WHERE ID = 1534781;
Is there a way to execute each row as a single sql query? Also, I'm using datagrip, if anyone knows of a sort of tool I would be happy.
To execute a file against your database in DataGrip just use the context menu when observing your file in Files tool window
A CSV file that contains one column is just called a "file." :-)
The most common way of executing a series of SQL statements in a file is with the command-line mysql client:
mysql -e "source myfile.csv"
How about script:
begin
update ...
update ...
update ...
...
end;

How to use a user variable in 'USE database' statement

I want to make the name of my MYSQL database variable, so it can be set from the outside (a python script) to whatever I like. Thus avoiding hardcoding the name of the database.
I tried passing the name via defining a user variable in the mysql client and then loading the sql script. I was able to create the database but not to connect to it via the USE statement
Definition of variable and calling the sql script:
mysql> SET #database_name = 'name';
mysql> SOURCE script.sql;
Code of script.sql:
-- creating database according to user variable
SET #query = CONCAT('CREATE SCHEMA IF NOT EXISTS ', #database_name, ' DEFAULT CHARACTER SET latin1');
PREPARE stmt FROM #query; EXECUTE stmt; DEALLOCATE PREPARE stmt;
-- selecting the database according to the user variable
SET #query = CONCAT('USE ', #database_name);
PREPARE stmt FROM #query; EXECUTE stmt; DEALLOCATE PREPARE stmt;
I expected that this would work, but unexpectedly MYSQL threw this error into my face:
This command is not supported in the prepared statement protocol yet
The problem is, that there are a lot of table defintions in this script, and they all need the actual database name in front of them, or the USE statement has to work, so the correct database is selected and no database name is needed when creating the tables.
I am grateful for any useful tips, thank you :).
A "complex" workaround might be to generate a .sql file if you have FILE privilege and the secure_file_priv system variable is set also max_allowed_packet also might to be changed.
# SET SESSION max_allowed_packet = '<>'; commented because it might be needed to generate larger .sql file
SET SESSION group_concat_max_len = ##max_allowed_packet;
SELECT
GROUP_CONCAT(sql_lines.line SEPARATOR ';');
FROM (
SELECT CONCAT('CREATE SCHEMA IF NOT EXISTS ', #database_name, 'DEFAULT CHARACTER SET latin1') AS line
UNION
SELECT CONCAT('USE ', #database_name) AS line
) AS sql_lines
CROSS JOIN (
SELECT #database_name = '<test>'
) AS init_user_param
INTO
DUMPFILE '<absolute_file_path>';
SOURCE script.sql;
There is a way, you can generate the sql like you were typing it on the sql prompt. You could write everything like you are typing it, but using a bash script:
Code like this (filename: generate-database.sh):
#!/bin/bash
mydatabase="mytest";
cat << EOF
create database $mydatabase;
use $mydatabase;
create table test1 (id int);
create table test2 (id int);
EOF
You can even pass the database name as the first parameter if you want to have a database for a different site. Then you would do something like this:
bash generate-database.sh | mysql -u <username> -p
Then that will do everything like you would do as if you were typing it in mysql.
To pass in as the first parameter you would do this:
mydatabase=$1;
On the command prompt you would do this:
bash generate-database.sh MarkTownsend | mysql -u <username> -p

Unix: Passing Param to MYSQL files from BASH Shell Script

I want to pass SOME VARIABLES to mysql file from bash shell script.
Here is my shell script.
#!/bin/bash
echo $0 Started at $(date)
mysql -uroot -p123xyzblabla MyMYSQLDBName<mysqlfile.sql PARAM_TABLE_NAME
Please note that it is MYSQL and not SQLPLUS
My MYSQL.sql , I want to read and use passed parameter/argument (PARAM_TABLE_NAME)
select count(*) from PARAM_TABLE_NAME
Question 1: What is the correct syntax to pass variable(PARAM_TABLE_NAME) to sql file (mysqlfile.sql)?
Question 2: How can I print variable(PARAM_TABLE_NAME) in sql file (mysqlfile.sql)?
Basically, I want to make generic SQL script which can load or select data from tables based on received inputs.
Thanks
There is no such thing as passing a parameter to a SQL file. A SQL file is no more than a text file that contains a list of SQL statements. These statements are interpreted by the mysql client program exactly as if you typed them on your keyboard.
The mysql client does not provide the feature you are looking for.
But I can think of a few tricks to achieve a similar effet:
create/populate a configuration table prior to reading your SQL file. Then write your SQL file so that it takes this table contents into account:
bash> mysql -e "INSERT INTO config_table VALUES(1, 2, 3)"
bash> mysql < script.sql
prepend your SQL file with some variables declarations. Then use these variables in the rest of your script:
bash> (echo "SET #var=123;" ; cat script.sql) |mysql
[example script.sql]
SELECT * FROM mytable WHERE id = #var;
write your SQL file with some placeholders that your replace on the fly, e.g with sed:
bash> sed "s/__VAR_A__/mytable/g" script.sql |mysql
[example script.sql]
SELECT * FROM __VAR_A__ WHERE id = 123;
All the above is quite dirty. A much cleaner solution would involve stored procedures or functions. Then you would just pass your parameters as procedure parameters:
bash> PARAM1='foo'; PARAM2='bar'
bash> mysql -e "CALL MyProc($PARAM1);"
bash> mysql -e "SELECT MyFunc($PARAM2);"
note: it is not possible to parametrize a table name in SQL, so you will need to resort to dynamic SQL like this in all cases (except for the sed-based hack, which I do not recommend)
This is an old thread but I think may still be useful to some people. Something like this should work:
mysql -uroot -p123xyzblabla MyMYSQLDBName -e "set #testVar='customer_name'; source mysqlfile.sql;"
Now #testVar (customer_name) is available for you to use in mysqlfile.sql file.
HTH
The way to pass parameters has already been answered in this or other threads. However, specific to the sample in you question, I'd like to add that you can't use the variables declaration method as a placeholder for a table name, as the documentation says:
User variables are intended to provide data values. They cannot be used directly in an SQL statement as an identifier or as part of an identifier, such as in contexts where a table or database name is expected
If you want to use a table name parameter, you can still use the sed or the stored procedures or functions as answered by #RandomSeed
In addition to that, another way is using PREPARE and EXECUTE in your script. The following example allows you to create a database/schema (in case you wanted to use stored procedures you need to have them already stored in a database), like this:
[myscript.sql]
set #s=CONCAT("CREATE DATABASE ", #dbname);
PREPARE stmt FROM #s;
EXECUTE stmt;
Then use any of the proposed syntax in the other questions to set the #dbname variable:
mysql -uroot -p123xyzblabla MyMYSQLDBName -e "set #dbname='mydatabase'; source myscript.sql;"

Can one line mysql commands be easily stored and re-used?

I find myself constantly typing in long commands such as:
mysql> SELECT Cust_Num, Cust_Name_Full, Email FROM customers;
Is there a way to save this command as, say, "CInf" and execute it with that simple shortcut command like this:
mysql> CInf; ( = mysql> SELECT Cust_Num, Cust_Name_Full, Email FROM customers; )
I'm thinking of something analogous to a DOS batch file, where you can simply type the name of the batch file, without even needing the .bat extension.
Also, where do I store these mysql "batch files" (note: these aren't .bat files to be run from a command window, these are run from the mysql> prompt). With DOS I'd have a C:/bat folder and I'd put C:/bat in the path environment variable. How do I do a similar thing for mysql?
Mysql doesn't have "macros", but if your statements are select queries (like your example) you can create views:
create view clnf as
SELECT Cust_Num, Cust_Name_Full, Email
FROM customers;
Then to use
select * from clnf;
The other approach is to store your SQL in files, then from the mysql prompt use the source command:
mysql> source file_name
which executes the contents of the SQL file as if you had pasted it in to the window.

How can I drop all MySQL Databases with a certain prefix?

I need to drop hundreds of mysql databases that all share a common prefix, but have random id's as the rest of their name ( eg. database_0123456789, database_9876543210 ). All these databases are on the same server. There are other databases on that same server that I don't want to drop.
This is what I'd like to do:
DROP DATABASE `database_*`;
How can I drop these efficiently? Is there a MySQL query I can run? Maybe a shell script?
The syntax of the DROP DATABASE statement supports only a single database name. You will need to execute a separate DROP DATABASE statement for each database.
You can run a query to return a list of database names, or maybe more helpful, to generate the actual statements you need to run. If you want to drop all databases that start with the literal string database_ (including the underscore character), then:
SELECT CONCAT('DROP DATABASE `',schema_name,'` ;') AS `-- stmt`
FROM information_schema.schemata
WHERE schema_name LIKE 'database\_%' ESCAPE '\\'
ORDER BY schema_name
Copy the results from that query, and you've got yourself a SQL script.
(Save the results as plain text file (e.g. dropdbs.sql), review with your favorite text editor to remove any goofy header and footer lines, make sure the script looks right, save it, and then from the mysql command line tool, mysql> source dropdbs.sql.)
Obviously, you could get more sophisticated than that, but for a one-time shot, this is probably the most efficient.)
Don't need of an external script file. A stored procedure using prepare statements might do the trick:
CREATE PROCEDURE kill_em_all()
BEGIN
DECLARE done INT DEFAULT FALSE;
DECLARE dbname VARCHAR(255);
DECLARE cur CURSOR FOR SELECT schema_name
FROM information_schema.schemata
WHERE schema_name LIKE 'database\_%' ESCAPE '\\'
ORDER BY schema_name;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
OPEN cur;
read_loop: LOOP
FETCH cur INTO dbname;
IF done THEN
LEAVE read_loop;
END IF;
SET #query = CONCAT('DROP DATABASE ',dbname);
PREPARE stmt FROM #query;
EXECUTE stmt;
END LOOP;
END;
Once you have that procedure, you just have to:
CALL kill_em_all();
When done:
DROP PROCEDURE kill_em_all
This question lacks an answer without creating a file first.
Our build server automatically creates a database for every topic branch while running unit tests. After information_schema queries get really slow which causes our tests to fail.
I created a batch file which runs every day. I did not want to deal with temporary files. So here is my solution.
#ECHO OFF
REM drops all databases excluding defaults
SET user=user
SET pass=pass
mysql ^
-u %user% ^
-p%pass% ^
-NBe "SELECT CONCAT('drop database `', schema_name, '`;') from information_schema.schemata where schema_name NOT IN ('mysql', 'test', 'performance_schema', 'information_schema')" | mysql -u %user% -p%pass%
Modifying spencer7593 answer
Here is the command to find desired results and save it in file where prefix is database prefix
SELECT CONCAT('DROP DATABASE ',schema_name,' ;') AS stmt
FROM information_schema.schemata
WHERE schema_name LIKE 'prefix\_%' ESCAPE '\\'
ORDER BY schema_name into outfile '/var/www/pardeep/file.txt';
if you get permission denied then change folder permission to 777 or change folder group to mysql using this
chown -R mysql /var/www/pardeep/
then run this query
source /var/www/pardeep/file.txt;