Documentation Home
MySQL 5.5 Reference Manual
Related Documentation Download this Manual Excerpts from this Manual SELECT ... INTO Syntax

The SELECT ... INTO form of SELECT enables a query result to be stored in variables or written to a file:

  • SELECT ... INTO var_list selects column values and stores them into variables.

  • SELECT ... INTO OUTFILE writes the selected rows to a file. Column and line terminators can be specified to produce a specific output format.

  • SELECT ... INTO DUMPFILE writes a single row to a file without any formatting.

The SELECT syntax description (see Section 13.2.9, “SELECT Syntax”) shows the INTO clause near the end of the statement. It is also possible to use INTO immediately following the select_expr list.

An INTO clause should not be used in a nested SELECT because such a SELECT must return its result to the outer context.

The INTO clause can name a list of one or more variables, which can be user-defined variables, stored procedure or function parameters, or stored program local variables. (Within a prepared SELECT ... INTO OUTFILE statement, only user-defined variables are permitted;see Section, “Local Variable Scope and Resolution”.)

The selected values are assigned to the variables. The number of variables must match the number of columns. The query should return a single row. If the query returns no rows, a warning with error code 1329 occurs (No data), and the variable values remain unchanged. If the query returns multiple rows, error 1172 occurs (Result consisted of more than one row). If it is possible that the statement may retrieve multiple rows, you can use LIMIT 1 to limit the result set to a single row.

SELECT id, data INTO @x, @y FROM test.t1 LIMIT 1;

User variable names are not case sensitive. See Section 9.4, “User-Defined Variables”.

The SELECT ... INTO OUTFILE 'file_name' form of SELECT writes the selected rows to a file. The file is created on the server host, so you must have the FILE privilege to use this syntax. file_name cannot be an existing file, which among other things prevents files such as /etc/passwd and database tables from being destroyed. The character_set_filesystem system variable controls the interpretation of the file name.

The SELECT ... INTO OUTFILE statement is intended primarily to let you very quickly dump a table to a text file on the server machine. If you want to create the resulting file on some other host than the server host, you normally cannot use SELECT ... INTO OUTFILE since there is no way to write a path to the file relative to the server host's file system.

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.

It is also possible to create the resulting file on a different host other than the server host, if the location of the file on the remote host can be accessed using a network-mapped path on the server's file system. In this case, the presence of mysql (or some other MySQL client program) is not required on the target host.

SELECT ... INTO OUTFILE is the complement of LOAD DATA INFILE. Column values are written converted to the character set specified in the CHARACTER SET clause. If no such clause is present, values are dumped using the binary character set. In effect, there is no character set conversion. If a result set contains columns in several character sets, the output data file will as well and you may not be able to reload the file correctly.

The syntax for the export_options part of the statement consists of the same FIELDS and LINES clauses that are used with the LOAD DATA INFILE statement. See Section 13.2.6, “LOAD DATA INFILE Syntax”, for information about the FIELDS and LINES clauses, including their default values and permissible values.

FIELDS ESCAPED BY controls how to write special characters. If the FIELDS ESCAPED BY character is not empty, it is used when necessary to avoid ambiguity as a prefix that precedes following characters on output:

  • The FIELDS ESCAPED BY character


  • The first character of the FIELDS TERMINATED BY and LINES TERMINATED BY values

  • ASCII NUL (the zero-valued byte; what is actually written following the escape character is ASCII 0, not a zero-valued byte)

The FIELDS TERMINATED BY, ENCLOSED BY, ESCAPED BY, or LINES TERMINATED BY characters must be escaped so that you can read the file back in reliably. ASCII NUL is escaped to make it easier to view with some pagers.

The resulting file does not have to conform to SQL syntax, so nothing else need be escaped.

If the FIELDS ESCAPED BY character is empty, no characters are escaped and NULL is output as NULL, not \N. It is probably not a good idea to specify an empty escape character, particularly if field values in your data contain any of the characters in the list just given.

Here is an example that produces a file in the comma-separated values (CSV) format used by many programs:

SELECT a,b,a+b INTO OUTFILE '/tmp/result.txt'
  FROM test_table;

If you use INTO DUMPFILE instead of INTO OUTFILE, MySQL writes only one row into the file, without any column or line termination and without performing any escape processing. This is useful if you want to store a BLOB value in a file.


Any file created by INTO OUTFILE or INTO DUMPFILE is writable by all users on the server host. The reason for this is that the MySQL server cannot create a file that is owned by anyone other than the user under whose account it is running. (You should never run mysqld as root for this and other reasons.) The file thus must be world-writable so that you can manipulate its contents.

If the secure_file_priv system variable is set to a nonempty directory name, the file to be written must be located in that directory.

In the context of SELECT ... INTO statements that occur as part of events executed by the Event Scheduler, diagnostics messages (not only errors, but also warnings) are written to the error log, and, on Windows, to the application event log. For additional information, see Section 20.4.5, “Event Scheduler Status”.

Download this Manual
User Comments
  Posted by Jorge Lumbreras on November 18, 2011
Is a Example... very simple.. que no tiene encabezados (No headers)

select * from control_pagos
into outfile 'c:\\data.csv'

para aplicar este procedimiento el usuario debe de tener privilegios de GRANT / FILE.

Este ejemplo le agregamos los encabezados (with headers)

select 'idPago','fecha','lead','idAlumno','idTipoPago','idGpo',
'mes','formaPago','observaciones' union all
(select id_control_pagos, fecha, lead, id_alumno, id_concepto_pago, id_Gpo,id_Taller,
id_docente, Pagoimporte, NoFactura, FacturaImporte, Mensualidad_No, FormaPago,
Observaciones from control_pagos
into outfile 'c:\\data.csv'

  Posted by Mauricio Aristizabal on March 23, 2012
OK, this is weird, I don't know if it's just a setting in my server or bad docs (unlikely), but I just spent a couple hours trying to get a select into [vars] working inside a function before I realized other people were not using @, and that got it working. So if you're having trouble, try (reusing docs example above):

SELECT id, data INTO x, y FROM test.t1 LIMIT 1;

instead of

SELECT id, data INTO @x, @y FROM test.t1 LIMIT 1;

  Posted by Linda McGarry on February 25, 2013
I wrote a generic procedure to export to CSV for Excel pivot tables - pass in the schema, table and output filename/path and it creates and executes the SQL. You will need to localise the date export format for your country and the line endings (I'm on Windows). I also assume you are calling the SQL from a command line that can delete any existing files before creating the new CSV file.

-- create procedure to export entire table to CSV with header for Excel pivot tables
-- - input: schema and table for export, file path for CSV file
delimiter $$

drop procedure if exists test.export_csv_proc

create procedure test.export_csv_proc(IN vSchema varchar(200), IN vTable varchar(200), IN vFilePath varchar(2000))

-- declare variables

declare vColumn varchar(200); -- field name
declare vDataType char(20); -- field data type
declare vOrdinalPosition smallint unsigned default 0; -- counter based on information_schema data
declare vMaxFields smallint unsigned default 0; -- number of fields in export table
declare vHeaderSQL text default ''; -- hold text for header export SQL
declare vDataSQL text default ''; -- hold text for data export SQL
declare vOutputSQL text default ''; -- combine all SQL into final code for exporting table
-- create cursor to get list of columns for export

declare cur_header cursor for
select distinct
from information_schema.columns as c
where c.table_schema = vSchema
and c.table_name = vTable
order by
-- how many columns are in the export table

set @pSQL = concat("
select @vFields:= max(c.ordinal_position)
from information_schema.columns as c
where c.table_schema = '", vSchema,
"' and c.table_name = '", vTable, "'"

prepare stmt from @pSQL;
execute stmt;
deallocate prepare stmt;

set vMaxFields = @vFields;
-- create SQL export text
-- - add double quote enclosure only for character fields
-- - format date fields for Excel import (DD/MM/YYYY)
-- - add comma after all but last field

open cur_header;

fetch cur_header into vColumn, vDataType, vOrdinalPosition;

set vHeaderSQL = concat(vHeaderSQL, '\'"\',', '\'', vColumn, '\'', ',\'"\'');

when vDataType in ('char','varchar') then set vDataSQL = concat(vDataSQL, '\'"\',ifnull(`', vColumn, '`,\'\'),\'"\'');
when vDataType in ('date','datetime','timestamp') then set vDataSQL = concat(vDataSQL, 'ifnull(date_format(`', vColumn, '`,\'%d/%m/%Y %T\'),\'\')');
else set vDataSQL = concat(vDataSQL, 'ifnull(`', vColumn, '`,\'\')');
end case;

if vOrdinalPosition < vMaxFields
then set vHeaderSQL = concat(vHeaderSQL, ',', '",", '),
vDataSQL = concat(vDataSQL, ',', '",", ')
end if;

until vOrdinalPosition = vMaxFields
end repeat;

close cur_header;
-- create CSV SQL text

set vOutputSQL = concat(
'select concat (',
') UNION select concat (',
') from ', vSchema, '.', vTable,
' into outfile "', vFilePath,
'" lines terminated by "\\r\\n"'
-- execute created statement

set @pSQL = vOutputSQL;

prepare stmt from @pSQL;
execute stmt;
deallocate prepare stmt;

delimiter ;
--call test.export_csv_proc('test_schema', 'test_table', 'c:/temp/test.csv');

  Posted by Graham Wideman on July 20, 2014
On Windows, it may not be obvious what path separator character(s) to use when specifying the file path in SELECT INTO OUTFILE.

First, if you use backslash, you must double them, as you would in writing a literal string in C or C-related languages:

SELECT whatever INTO OUTFILE 'D:\\Temp\somefile'...

Because MySQL doesn't overwrite that file, you may be persuaded to change the filename each time around, by using a variable (perhaps a timestamp) for the file name:

SET @filepath = CONCAT('D:\\Temp\somefile\\TheFile_', @variablepart);
SELECT whatever INTO OUTFILE @filepath...

However, this isn't legal syntax because a variable isn't allowed at that location. So instead you might move to preparing the SELECT .. INTO statement. That works, but then the filepath string goes through two steps of unescaping, so you'll need to double escape the path separators (ie: four backslashes).

SET @filepath = CONCAT('D:\\\\Temp\somefile\\\\TheFile_', @variablepart);

Probably a better solution is to use a single forward slash instead, which MySQL apparently converts to the platform-appropriate separator when calling the OS API.

SET @filepath = CONCAT('D:/Temp/somefile/TheFile_', @variablepart);

Sign Up Login You must be logged in to post a comment.