SQL Questions

A UNION query combines the output from multiple queries and must include the same number of columns.

SELECT YEAR(GETDATE()) as "Year";

One can use simple conditions like >= and <=, or use between/and but the trick here is to know your exact data type.

- Sometimes date fields contain time and that is where the query can go wrong so it is recommended to use some date related functions to remove the time issue. In SQL Server common function for accomplishing the task datediff () function.

- Interviewees also have to be aware of different time zones and server time zone.

-To increase query performance you may still want to use between however you should be aware of proper format you should use if not it might misbehave during filtering.

SQL Server can be linked to any server provided it has OLE-DB provider from Microsoft to allow a link. E.g. Oracle has an OLE-DB provider for oracle that Microsoft provides to add it as linked server to SQL Server group.

In SQL, a SQL view is a virtual table based on the result-set of an SQL statement. A view contains rows and columns, just like a real table.

SQL views can be used to hide rows and columns and complicated SQL syntax.

The fields in a view are fields from one or more real tables in the database.

SELECT *FROM Employees WHERE EmpName like ‘M%’.