LOAD DATA INFILE / PHP MySQLi / Adding additional columns/values for inputted & dealing with NULL values

Question

I have been experimenting with LOAD DATA INFILE and there are a couple things I would like to be able to do. I'm not sure if they are possible, or if I may need to create a temporary table for the upload.

When a CSV file is uploaded/inputed in my application, I'd like to have an auto-incrementing column for the rows. In addition, I'd like to add a column value to each row identifying the user who uploaded the file.

I am using PHP/MySQLi on a InnoDB database.

I may also have empty strings for null values in my CSV files. Is there a simple way to input these values as NULL into the database?

Thanks for all your help!

Answer 1

to achieve what you want, you would need to programmatically pre-create the table first along with a triggers function prior to loading data into it.

therefore, create the table first with triggers:

example:

 CREATE TABLE foo (
    id INT NOT NULL AUTO_INCREMENT,
    fooitems TEXT,
    PRIMARY KEY (id)
 );

 CREATE TRIGGER fooblank2null
 BEFORE INSERT ON foo
 FOR EACH ROW
 SET NEW.fooitems=IF(TRIM(NEW.fooitems)='',NULL,NEW.fooitems);

to test if the trigger works:

 INSERT INTO foo (fooitems)
 VALUES
 ('i'),(''),('am'),('foo'),(' '),('.');

you can now load the data to the specific column.

example:

 LOAD DATA
 INFILE 'foo.txt'
 INTO TABLE foo
 FIELDS TERMINATED BY ',' ENCLOSED BY '"'
 LINES TERMINATED BY '\n'
 (fooitems);