Part 2: Learning LINQ from SQL using Visual Basic 2008 – WHERE operator

To execute the LINQ statements provided in this post, I suggest you to go through Part-1 (http://jagchat.spaces.live.com/blog/cns!41050F68F010A662!913.entry), where I demonstrated the same.

 

A simple example on WHERE operator of LINQ:

The following SQL SELECT

     SELECT ename, sal FROM emp WHERE sal > 6000

can be coded in LINQ as following:     

Dim query = From p In GetEmployeeList()

Select p.Ename, p.Sal

Where Sal > 6000

Using LIKE with WHERE operator of LINQ:

The following SQL SELECT

     SELECT ename, sal FROM emp WHERE ename LIKE ‘J%’

can be coded in LINQ as following:     

Dim query = From p In GetEmployeeList()

Select p.Ename, p.Sal

            Where Ename Like "J*"

The following SQL SELECT

     SELECT ename, sal FROM emp WHERE ename LIKE ‘W_____’

can be coded in LINQ as following:     

Dim query = From p In GetEmployeeList()

Select p.Ename, p.Sal

            Where Ename Like "W?????"

 

Combined example of SELECT, WHERE and ORDER BY operators in LINQ:

The following SQL SELECT

     SELECT ename, sal FROM emp WHERE deptno = 10 ORDER BY deptno DESC

can be coded in LINQ as following:     

Dim query = From p In GetEmployeeList()

Where p.Deptno = 10

Order By p.Deptno Descending

Select p.Ename, p.Sal

Note: If other operators (WHERE, ORDER BY etc.) are using the columns not listed in SELECT, they need to be moved before SELECT (as above)