问题
I was kinda surprised when I saw following:
CREATE TEMPORARY TABLE X (ID int) AS SELECT NumColumn FROM Table
I have tried to google it but only found using this as alieases. What this use actually is? I feel bit confused since I was stupidly creating temporary table and then fill it by using of insert..
Thank you
回答1:
Its how you create a temporary table and populate it with the results of a select query.
You can see it in the documentation at the very bottom of the CREATE TABLE specification
select_statement:
[IGNORE | REPLACE] [AS] SELECT ... (Some legal select statement)
回答2:
This will create a temporary table for you but just remember that this will not bring along any indexes you had on the original table. For that reason, sometimes it may be better create a complete copy of the table definition using
create table x like y;
Since this only creates an EMPTY table, you need to also run
insert into x (col1) select col1 from y;
回答3:
CREATE TABLE (table name) AS SELECT * FROM (existing table name);
this command for copy whole table in to another table;
来源：https://stackoverflow.com/questions/2471343/using-as-in-mysql-not-as-aliases