ProjectionPushDown rule don't consider the alias in projection. #4174
Description
Describe the bug
It's from #4141
when just need c1, but due to alias, projection will contains c1 and its alias column(if exists).
like tablescan include c1, c2, if we project c1 as c2, projection include [c1, c2].
It's because the pushdown project rule don't handle alias. In fact, when handle projection with alias, we need replace the alias column in new_required_columns, but if we see the code of this rule, we can find that it didn't consider alias.
For example:
project c1 as c2
tablescan c1.
when we meet project c1 as c2, if new_required_columns include c2, we need replace it with c1.
It's a future ticket, I have debug this rule, I will try to fix it.
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