Is it possible to insert multiple rows at a time in an SQLite database?

Question

In MySQL you can insert multiple rows like this:

INSERT INTO \'tablename\' (\'column1\', \'column2\') VALUES
    (\'data1\', \'data2\'),
    (\'data1\', \'da         


        

Answer 1

If you are using bash shell you can use this:

time bash -c $'
FILE=/dev/shm/test.db
sqlite3 $FILE "create table if not exists tab(id int);"
sqlite3 $FILE "insert into tab values (1),(2)"
for i in 1 2 3 4; do sqlite3 $FILE "INSERT INTO tab (id) select (a.id+b.id+c.id)*abs(random()%1e7) from tab a, tab b, tab c limit 5e5"; done; 
sqlite3 $FILE "select count(*) from tab;"'

Or if you are in sqlite CLI, then you need to do this:

create table if not exists tab(id int);"
insert into tab values (1),(2);
INSERT INTO tab (id) select (a.id+b.id+c.id)*abs(random()%1e7) from tab a, tab b, tab c limit 5e5;
INSERT INTO tab (id) select (a.id+b.id+c.id)*abs(random()%1e7) from tab a, tab b, tab c limit 5e5;
INSERT INTO tab (id) select (a.id+b.id+c.id)*abs(random()%1e7) from tab a, tab b, tab c limit 5e5;
INSERT INTO tab (id) select (a.id+b.id+c.id)*abs(random()%1e7) from tab a, tab b, tab c limit 5e5;
select count(*) from tab;

How does it work? It makes use of that if table tab:

id int
------
1
2

then select a.id, b.id from tab a, tab b returns

a.id int | b.id int
------------------
    1    | 1
    2    | 1
    1    | 2
    2    | 2

and so on. After first execution we insert 2 rows, then 2^3=8. (three because we have tab a, tab b, tab c)

After second execution we insert additional (2+8)^3=1000 rows

Aftern thrid we insert about max(1000^3, 5e5)=500000 rows and so on...

This is the fastest known for me method of populating SQLite database.