Oracle (SQL) Questions

1. False about group functions?

where clause cant be used to reduce groups, having clause can be used to reduce groups, where clause can't have group functions

2. Simple expression can be a

constant, column name, variable, scalar function

3. how many null values do columns with not null and unique constraint allow

1, 2, any, none

4. There is no native regular expression support in SQL Server.

True/False