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/