How to merge two large tables into one?

Question

SQLite

Greetings,

There are two tables with a dimension of 20 million and 10 million records, respectively
. The first table contains 5 fields, the second 3 fields that the first table also contains

. Is there any way to combine tables into one and with the correct ratio of fields?

Answer 1

In a table with 5 fields (A), create a unique index on the common identifier/s.
Then

INSERT OR IGNORE INTO A (col1, col2, col3)
SELECT col1, col2, col3 FROM B;

Something like this.