Pollard, Mike schrieb:
If count(<col>) convert <col> to a string (an assumption that Martijn has cast into doubt, or perhaps shredded), then rather than convert all non-nulls that are not a string into a string, I was proposing converting the values into an int with the values 0 or 1 (0 means that row was null for that column, 1 means that row was not null;, since count(<col>) means count the non-null rows in <col>).
I'm not getting how you got this idea of count() doing any conversion? It does not and there is nothing in the docs wich would lead to this.
Anyway, to make a short story long. The idea is rather than convert the column into a string, convert it into a value indicating whether the column was null or not null (which is all count cares about). In any case, it's moot idea since it appears Postgres already does that.
No, count does not convert. It just counts all non null values. If you want to count rows, just use count(*). ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
