hive SELECT Statement Select: Project selected columns
Example
Sample table (say Employee) structure
| Column Name | Datatype |
|---|---|
| ID | INT |
| F_Name | STRING |
| L_Name | STRING |
| Phone | STRING |
| Address | STRING |
Project all the columns
Use wild card * to project all the columns. e.g.
Select * from Employee
Project selected columns (say ID, Name)
Use name of columns in the projection list. e.g.
Select ID, Name from Employee
Discard 1 column from Projection list
Display all columns except 1 column. e.g.
Select `(ID)?+.+` from Employee
Discard columns matching pattern
Reject all columns which matches the pattern. e.g. Reject all the columns ending with NAME
Select `(.*NAME$)?+.+` from Employee
