我可以使用变量在mysql中指定OUTFILE吗 [英] can I use a variable to specify OUTFILE in mysql

问题描述

是否可以执行以下操作?这不起作用，但是显示了我想做什么

Is there a way to do something like the following ? which doesn't work but shows what I want to do

SET @OutputPath = '/Users/jo/Documents'
SET @fullOutputPath = CONCAT(@OutputPath,'/','filename.csv')
SET @fullOutputPath2 = CONCAT(@OutputPath,'/','filename2.csv')

SELECT * INTO OUTFILE @fullOutputPath
FIELDS TERMINATED BY ',' 
OPTIONALLY ENCLOSED BY '"'
FROM database.tableName;

SELECT * INTO OUTFILE @fullOutputPath2
FIELDS TERMINATED BY ',' 
OPTIONALLY ENCLOSED BY '"'
FROM database.tableName2;

推荐答案

编辑:不使用变量(仅常量值)将数据(例如表)保存到文件中

Saving data(e.g. a table) into file without using variable (only constant values)

-- folder_path could could be like => c:/users/sami
-- choose the directory/folder already available in system
-- and make sure you have access to write the file there

SELECT * INTO OUTFILE 'folder_path/filename.csv'
FIELDS TERMINATED BY ',' 
OPTIONALLY ENCLOSED BY '"'
FROM database.tableName;

现在使用变量

每当必须在sql中使用变量名时，就需要动态sql(仅适用于存储过程，不适用于简单的sql查询或触发器或函数)

Whenever you have to use a variable name in sql, you need dynamic sql (which is applicable in stored procedures only, neither in simple sql query nor in triggers or functions)

SET @OutputPath := 'Users/jo/Documents'; //or any folder_path
SET @fullOutputPath := CONCAT(@OutputPath,'/','filename.csv');
SET @fullOutputPath2 := CONCAT(@OutputPath,'/','filename2.csv');

set @q1 := concat("SELECT * INTO OUTFILE ",@fullOutputPath,
" FIELDS TERMINATED BY ',' 
OPTIONALLY ENCLOSED BY '\"'
FROM database.tableName");

set @q2 := concat("SELECT * INTO OUTFILE ",@fullOutputPath2,
" FIELDS TERMINATED BY ',' 
OPTIONALLY ENCLOSED BY '\"'
FROM database.tableName2");

prepare s1 from @q1;
execute s1;deallocate prepare s1;

prepare s1 from @q2;
execute s1;deallocate prepare s1;

由于您的查询中已经同时包含了'和"，因此我使用"连接了您的查询，并使用\来转义原始的"，以确保其用作文字字符，而不用于串联

As you had both ' and " in your query already, so I concatenated your query using " and used \ to escape your original " to ensure its use as a literal character and not used for concatenation

我刚刚告诉了variable在sql中的用法.首先，您应该确保查询是否像顶部的示例一样工作(不使用变量)

I just told the use of variable in sql. First You should make sure if your query works like example at the top (without using variable)

结论:如果您的上述查询工作正常，那么您在某些存储过程中使用它时，我告诉的动态sql也将正常工作.

Conclusion: If your above query works fine then my told dynamic sql will work as well given that you are using it in some stored procedure.

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