Which one is faster - below is 2 form for table creation with data. Which one is faster ?
We are using teradata 16.20.
Assuming the structure of T2 matches T1 there should be no real difference as far as actually inserting the data..
But clearly CREATE TABLE AS will have some extra overhead to create the table, so you should expect that to take just a bit longer.
And if someone claims that CREATE * INSERT is much better than CREATE TABLE AS it's usually because the latter was a CREATE TABLE AS (SELECT ...) without defining the PI, which results in a (maybe bad) PI on the 1st column (and maybe a change from MULTISET to SET).