Syntax
------

INSERT [LOW_PRIORITY | HIGH_PRIORITY] [IGNORE]
  [INTO] tbl_name [(col_name,...)]
  SELECT ...
  [ ON DUPLICATE KEY UPDATE col_name=expr, ... ]

Description
-----------

With INSERT ... SELECT, you can quickly insert many rows into a table from one
or more other tables. For example:

INSERT INTO tbl_temp2 (fld_id)
 SELECT tbl_temp1.fld_order_id
 FROM tbl_temp1 WHERE tbl_temp1.fld_order_id > 100;

tbl_name can also be specified in the form db_name.tbl_name (see Identifier
Qualifiers). This allows to copy rows between different databases.

If the new table has a primary key or UNIQUE indexes, you can use IGNORE to
handle duplicate key errors during the query. The newer values will not be
inserted if an identical value already exists.

REPLACE can be used instead of INSERT to prevent duplicates on UNIQUE indexes
by deleting old values. In that case, ON DUPLICATE KEY UPDATE cannot be used.

INSERT ... SELECT works for tables which already exist. To create a table for
a given resultset, you can use CREATE TABLE ... SELECT.

URL: https://mariadb.com/kb/en/insert-select/