MySQL checks whether a temporary table exists and creates a temporary table if it does not exist.

CREATETEMPORARYtableIFNOTEXISTSalarmLeveltb (devIDbigintnotnull, alarmLevelbigintnotnull); truncate

Create temporary table if not exists alarmLeveltb (devID bigint not null, alarmLevel bigint not null); truncate

Create temporary table if not exists alarmLeveltb
(DevID bigint not null,
AlarmLevel bigint not null
);

Truncate TABLE alarmLeveltb; -- clear data in the TABLE

Where: alarmLeveltb is the name of the temporary table.

The definitions of the temporary table are in parentheses.

Function: determines whether the temporary table alarmleveltb exists. If not, create a temporary table alarmLeveltb.