使用MySQL查询mysql，放置空字段并以CSV格式导出数据

Question

What would be the best approach to create a CSV file that contains 100+ fields where only 1/3 is actually being used?

A simple example is (bear with me):

If I have a 5 column table (X,O,#,T,P) with X amount of rows and the csv format needs to be

X,,,,O,,,,T,P,,,,,,#,,,

Thanks!

Answer 1

您可以使用mysql查询直接将表数据导出到csv文件

"SELECT column1, column2, column3 INTO OUTFILE '<filename>' FIELDS TERMINATED BY ',' ENCLOSED BY '\"' ESCAPED BY '\\' LINES TERMINATED BY '\r\n' FROM table1;"

Answer 2

One approach is you can place dummy columns in select query itself and then just create a CSV from the output:

select X,'','','',O,'','','',T,P,'','','','','',#,'','' from table_name; // this will by default give you your CSV structured output.

$fp = fopen('file_name', 'w');

fputcsv($fp, $values);

Answer 3

You can create lots of empty fields in the SELECT clause

SELECT X, '' AS col2, '' AS col3, '', O, '', '', '', '', T, P, '', '', '', '', '', '', `#`, '', ''
INTO OUTFILE 'filename.csv'
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
LINES TERMINATED BY '\n'
FROM yourTable;

When reading the file back into the table, you can specify which fields of the file go into the table like this:

LOAD DATA INFILE 'filename.csv'
INTO TABLE yourTable
(X, @dummy, @dummy, @dummy, O, @dummy, @dummy, @dummy, @dummy, T, P, @dummy, @dummy, @dummy, @dummy, @dummy, @dummy, `#`, @dummy, @dummy);

The @dummy variables receive the values of those file fields, while the column names receive those file fields.