如何使用C＃应用程序从mysql服务器导出csv文件，并在导出的csv文件的顶部获取所有列名

Question

I looked for a similar question but didnt find a solution for my problem. I developed a C# program which communicates with a mysql server.

I try to export a table from the mysql server to a csv file including the names of each column in the top. It's working, but theres a problem. When I use the following code:

string query = "SELECT /*here i insert column names*/ 
UNION SELECT /*here i insert column names*/ 
FROM `tableName` INTO OUTFILE /*here I insert the path*/ 
\ FIELDS TERMINATED BY ';' LINES TERMINATED BY '\n'";

It works, but I have to write each column. Is there a possibility to avoid that? So I could use the * operator so it looks like:

string query = "SELECT * 
UNION SELECT * 
FROM `tableName` INTO OUTFILE /*here I insert the path*/ 
\ FIELDS TERMINATED BY ';' LINES TERMINATED BY '\n'";

Because this Code is not working for me.

Answer 1

You can get all column names from your table with following statement:

SELECT COLUMN_NAME, ORDINAL_POSITION FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'Bundle'

Export your rows -> Get all column names using above statement -> Write your result to the beginning of your file using C#

This is how I would do this. Another possibility is a dynamic pivot which is much more complicated.

EDIT

Since OP mentioned that he may not have access to the exported file, here is a quick and dirty statement achieving the wanted result:

DECLARE @DataList varchar(500);
SELECT @DataList = COALESCE(@DataList + ',', '') + 'CAST(' + COLUMN_NAME + ' AS varchar(255))'
FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'YOURTABLE'

DECLARE @PivotList varchar(500);
SELECT @PivotList = COALESCE(@PivotList + ',', '') + COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'YOURTABLE'

DECLARE @GroupList varchar(500);
SELECT @GroupList = COALESCE(@GroupList + ',', '') + 'MIN(CAST(' + COLUMN_NAME + ' AS varchar(255)))'
FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'YOURTABLE'

DECLARE @Query varchar(1000)
SET @Query = '
SELECT ' + @GroupList + ' FROM INFORMATION_SCHEMA.COLUMNS 
PIVOT
(MAX(COLUMN_NAME) FOR COLUMN_NAME IN (' + @PivotList + ')) AS B
WHERE TABLE_NAME = ''YOURTABLE''
GROUP BY TABLE_NAME
UNION ALL
SELECT ' + @DataList + ' FROM YOURTABLE'
EXEC (@Query)

I hope this works for you!

Regards.