Loading multiple CSV files with SQLite

I ran into a similar problem and the comments to your question actually gave me the answer that finally worked for me

Step 1: merge the multiple csv's into a single file. Exclude the header for most of them but write down the header from one of them in the beginning.

Step 2: Load the single merged csv into SQLite.

For step 1 I used:

$ head -1 one.csv > all_combined.csv
$ tail -n +2 -q *.csv >> all_combined.csv

The first command writes only the first line of the csv file (you can choose whichever one file), the second command writes the whole document starting from line 2 and therefore excluding the header. The -q option makes sure that tail never writes the file name as a header.

Make sure to put all_combined.csv in a separate folder, or in some distributions, it will be included recursively!

To load into SQLite (Step 2) the answer given by Hot Licks worked for me:

 sqlite> .mode csv
 sqlite> .import all_combined.csv my_new_table

This assumes that my_new_table hasn't been created. Alternatively you can create beforehand and then load, but in that case exclude the header from Step 1.

I didn't find a nicer way to solve this so I used find along with xargs to avoid creating a huge intermediate .csv file:

find . -type f -name '*.csv' | xargs -I% sqlite3 database.db ".mode csv" ".import % new_table" ".exit"

find prints out the file names and the -I% parameter to xargs causes the command after it to be run once for each line, with % replaced by a name of a csv file.

http://www.sqlite.org/cli.html --

Use the ".import" command to import CSV (comma separated value) data into an SQLite table. The ".import" command takes two arguments which are the name of the disk file from which CSV data is to be read and the name of the SQLite table into which the CSV data is to be inserted.

Note that it is important to set the "mode" to "csv" before running the ".import" command. This is necessary to prevent the command-line shell from trying to interpret the input file text as some other format.

sqlite> .mode csv
sqlite> .import C:/work/somedata.csv tab1

There are two cases to consider: (1) Table "tab1" does not previously exist and (2) table "tab1" does already exist.

In the first case, when the table does not previously exist, the table is automatically created and the content of the first row of the input CSV file is used to determine the name of all the columns in the table. In other words, if the table does not previously exist, the first row of the CSV file is interpreted to be column names and the actual data starts on the second row of the CSV file.

For the second case, when the table already exists, every row of the CSV file, including the first row, is assumed to be actual content. If the CSV file contains an initial row of column labels, that row will be read as data and inserted into the table. To avoid this, make sure that table does not previously exist.

Note that you need to make sure that the files DO NOT have an initial line defining the field names. And, for "hundreds" of files you will probably want to prepare a script rather than typing in each file individually.

You can use DB Browser for SQLite to do this pretty easily. File > Import > Table from CSV file... and then select all the files to open them together into a single table.

I just tested this out with a dozen CSV files and got a single 1 GB table from them without any work. As long as they have the same schema, DB Browser is able to put them together. You'll want to keep the 'Column Names in first line' option checked.