MS SQL Stored Procedure for counting Dynamic table items - sql

Question

I had wrote this below stored procedure and getting incorrect statement.
ALTER PROCEDURE dbo.[Counter]
#TableName VARCHAR(100)
AS
BEGIN
DECLARE #Counter INT
DECLARE #SQLQ VARCHAR(200)
SET NOCOUNT ON;
--SET #TableName = 'Member';
SET #SQLQ = 'SELECT COUNT(*) FROM dbo.[' + #TableName + ']';
--Preparing the above sql syntax into a new statement(get_counter).
--Getting an error here I had googled the prepare statement but don't know why facing this error.
PREPARE get_counter FROM #SQLQ;
#Counter = EXEC get_counter; -- here #resutl gets the value of the count.#TableName
DEALLOCATE PREPARE get_counter; -- removing the statement from the memory.
END
Then I had wrote another one:
ALTER PROCEDURE dbo.[Counter]
#TableName VARCHAR(100)
AS
BEGIN
DECLARE #Counter INT
DECLARE #SQLQ VARCHAR(200)
SET NOCOUNT ON;
--SET #TableName = 'Member';
SET #SQLQ = 'SELECT COUNT(*) FROM dbo.[' + #TableName + ']';
--Preparing the above sql syntax into a new statement(get_counter).
Execute #SQLQ; -- here #resutl gets the value of the count.#TableName
--DEALLOCATE PREPARE get_counter; -- removing the statement from the memory.
Return #Counter;
END
It is running fine but I can't get the result in the Counter , anyone please help me(I know that I haven't assigned any value to the counter but if I do I get error).
After your answer martin I had replace my code with yours now its :
ALTER PROCEDURE dbo.[Counter] #SchemaName SYSNAME = 'dbo' , #TableName SYSNAME
AS
BEGIN
SET NOCOUNT ON;
DECLARE #SQLQ NVARCHAR(1000)
DECLARE #Counter INT;
SET #SQLQ = 'SELECT #Counter = COUNT(*) FROM ' +
Quotename(#SchemaName) + '.' + Quotename(#TableName);
EXEC sp_executesql
#SQLQ ,
N'#Counter INT OUTPUT',
#Counter = #Counter OUTPUT
Return SELECT #Counter
END
Now I had retrieved it .
ALTER PROCEDURE dbo.[CreateBusinessCode]
#MemberID bigint,
#len int,
#RewardAccountID bigint,
#ConnectionStatusID tinyint,
#Assign smalldatetime
AS
BEGIN
SET NOCOUNT ON;
DECLARE #counter INT
EXEC #counter = dbo.Counter 'dbo','member';
Select #counter;
END

Answer 1

You should use SYSNAME for object identifiers and Quotename rather than concatenating the square brackets yourself.
ALTER PROCEDURE dbo.[Counter] #TableName SYSNAME,
#SchemaName SYSNAME = 'dbo'
AS
BEGIN
SET NOCOUNT ON;
DECLARE #SQLQ NVARCHAR(1000)
DECLARE #Counter INT;
SET #SQLQ = 'SELECT #Counter = COUNT(*) FROM ' +
Quotename(#SchemaName) + '.' + Quotename(#TableName);
EXEC sp_executesql
#SQLQ ,
N'#Counter INT OUTPUT',
#Counter = #Counter OUTPUT
SELECT #Counter
END

Answer 2

In SQL Server, if you want to get a result into a variable, you have two choices.
The first is to use cursors.
The second is to do dynamic SQL:
declare #sql varchar(max) = whatever;
declare #cnt int;
declare #cntTable table as (cnt int);
insert into #cntTable
exec(#sql);
select #cnt = t.cnt
from #cntTable
It is cumbersome, but one or the other does work.

Answer 3

try this one.It doesnt query the actual table but will provide you the count of rows.This is better way if you have large tables and you need approximate count.
ALTER PROCEDURE dbo.[Counter]
#TableName VARCHAR(100)
AS
begin
declare #objectid int,#counter int
select #objectid = object_id from sys.all_objects where name = #tablename and schema_id=SCHEMA_ID('dbo')
select #counter = sum(rows) from sys.partitions where object_id= #objectid
and index_id in (0,1)
select #counter
end
go