The following list indicates limitations on the use of
TEMPORARY tables:
A TEMPORARY table can only be of type
HEAP, ISAM,
MyISAM, MERGE, or
InnoDB.
Temporary tables are not supported for MySQL Cluster.
You cannot refer to a TEMPORARY table
more than once in the same query. For example, the
following does not work:
mysql> SELECT * FROM temp_table, temp_table AS t2;
ERROR 1137: Can't reopen table: 'temp_table'
The SHOW TABLES statement
does not list TEMPORARY tables.
You cannot use RENAME to rename a
TEMPORARY table. However, you can use
ALTER TABLE instead:
mysql> ALTER TABLE orig_name RENAME new_name;
There are known issues in using temporary tables with replication. See Section 14.7, “Replication Features and Issues”, for more information.

User Comments
Combine queries for Insert and Select always obeys Innodb locking rules
if one of the source table is based on Innodb engine.
It is also possible that the INSERT activity applicable to TEMPORARY
table which is not InnoDB engine. It is also possible that in SELECT
section with INNODB, some other TEMPORARY Tables are used.
Devang Modi
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