s**********i
发帖数: 711 | 1 I read that a temp table is always created for
joins, with number of rows equals to the multiple
of all tables. is this true? sounds terrible if
I join two or more tables if the rows are not small... | c******r
发帖数: 512 | 2
It is not true.
【在 s**********i 的大作中提到】
: I read that a temp table is always created for
: joins, with number of rows equals to the multiple
: of all tables. is this true? sounds terrible if
: I join two or more tables if the rows are not small...
| xt
发帖数: 17532 | 3 It is wrong. That is the mathematical expression of joins,
but it has nothing to do with the real time joins. | n**m
发帖数: 255 | 4 But as know, it temp storage(we call it workfile) did been generated in
non-top level join. Certainly, it is not the representation of the
mathematical expression. Instead, it ususally only contains column/rows
that requried.
【在 xt 的大作中提到】
: It is wrong. That is the mathematical expression of joins,
: but it has nothing to do with the real time joins.
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