Count table row in dynamic sql : Count « Aggregate Functions « SQL Server / T-SQL Tutorial

3> CREATE TABLE Orders (
4>      OrderID int IDENTITY (1, 1) NOT NULL ,
5>      CustomerID nchar (5) NULL ,
6>      EmployeeID int NULL ,
7>      OrderDate datetime NULL ,
8>      RequiredDate datetime NULL ,
9>      ShippedDate datetime NULL ,
10>     ShipVia int NULL ,
11>     Freight money NULL DEFAULT (0),
12>     ShipName nvarchar (40) NULL ,
13>     ShipAddress nvarchar (60) NULL ,
14>     ShipCity nvarchar (15) NULL ,
15>     ShipRegion nvarchar (15) NULL ,
16>     ShipPostalCode nvarchar (10) NULL ,
17>     ShipCountry nvarchar (15) NULL
18> )
19> GO
1>
2> DECLARE @schemaname AS NVARCHAR(128), @tablename AS NVARCHAR(128);
3> SET @schemaname = N'dbo';
4> SET @tablename = N'Orders';
5>
6> DECLARE @objectname AS NVARCHAR(517);
7> SET @objectname = QUOTENAME(@schemaname) + N'.' + QUOTENAME(@tablename);
8> EXEC(N'SELECT COUNT(*) FROM ' + @objectname + N';');
9> GO

-----------
          0
1>
2> drop table orders;
3> GO

9.3.Count
	9.3.1.	COUNT returns the total count of records in a column or the count for DISTINCT (unique) values selected by the query.
	9.3.2.	COUNT(*) returns the total count of all records (rows) in the column, including NULL values of selected records by the query.
	9.3.3.	Count function with column alias
	9.3.4.	Counting unique values.
	9.3.5.	A common mistake with DISTINCT is to code the DISTINCT statement before the COUNT statement.
	9.3.6.	Counting values including NULL values.
	9.3.7.	Using ISNULL to count all values including NULLs.
	9.3.8.	Count table row in dynamic sql