Inserting data using stored procedure

Question

Using SQL Server Express 2014, I'm creating a stored procedure to accept parameters and convert data from a staging table to a production table. The parameters specify the table names and a field to lookup in another table. This is the first stored procedure
I've tried to create by myself though and I'm basing it on a guide. Here's what I've got so far:
CREATE PROCEDURE [dbo].[stp_UpdateAggregatePerf]
@prod_tbl NVARCHAR(250), @stg_tbl NVARCHAR(250), @customer NVARCHAR(20)
AS
BEGIN
DECLARE @p NVARCHAR(250), @s NVARCHAR(250), @c NVARCHAR(20), @cid int, @sql NVARCHAR(MAX)
SET @p = @prod_tbl
SET @s = @stg_tbl
SET @c = @customer
SET @cid = 'SELECT [dbo].[Customers].[CustomerID]
FROM dbo.customers
WHERE [dbo].[Customers].[CustomerName] LIKE ' + @c
SET @sql = 'INSERT INTO ' + @prod_tbl + '
SELECT CONVERT (datetime,TimeIndex,103) AS TimeIndex,
CONVERT(decimal(10,3),user_reads,3) AS Reads,
CONVERT(decimal(10,3), user_writes,3) AS Writes,
CONVERT(decimal,10,3),total_transfers,3) AS Total,
CONVERT(decimal(10,3),cp_reads,3) AS CPReads,
SUBSTRING(AggregateName,1,25),
SUBSTRING(ControllerName,1,25),
SUBSTRING(@cid,1,25)
FROM' + @stg_tbl
EXEC sp_executesql @sql
SET @sql = 'DROP TABLE' + @stg_tbl
EXEC sp_executesql @sql
END
So it should accept the parameters, take the customer name parameter and look up the customer ID field from another table to use in the last column, then generate and run the INSERT INTO statement to convert and transfer data, then drop the staging table.
I'm not sure how to go about using the INSERT statement with variables though, or even if I'm concatenating the string together correctly.
Here's my CREATE statements for the tables:
prod table:
CREATE TABLE [dbo].[AggregatePerf](
[AggrPerfID] [int] IDENTITY(1,1) NOT NULL,
[AggregateName] [varchar](25) NOT NULL,
[TimeIndex] [datetime] NOT NULL,
[Reads] [decimal](10, 3) NOT NULL,
[Writes] [decimal](10, 3) NOT NULL,
[Total] [decimal](10, 3) NOT NULL,
[CPReads] [decimal](10, 3) NOT NULL,
[ControllerName] [varchar](25) NOT NULL,
[CustomerID] [varchar](10) NOT NULL,
CONSTRAINT [PK_AggregatePerf] PRIMARY KEY CLUSTERED
[AggrPerfID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
Staging:
CREATE TABLE [dbo].[$tablename] (
[TimeIndex] VARCHAR(100)
, [user_reads] VARCHAR(100)
, [user_writes] VARCHAR(100)
, [cp_reads] VARCHAR(100)
, [total_transfers] VARCHAR(100)
, [AggregateName] VARCHAR(100)
, [ControllerName] VARCHAR(100)
The staging table is generated from PowerShell to import CSVs but I'm past that stage of the project now. I hope you can help  me get an understanding here as once I wrap my around one table I can apply the same technique to others.
Thanks in advance
Adam

Answer 1

Why do you provide a tables as a parameters? I think you may avoid using dynamic sql and simple use a static one.
Where do you use @cid
variable?
Static SQL may look like
SELECT @cid=
[dbo].[Customers].[CustomerID]
FROM dbo.customers
WHERE [dbo].[Customers].[CustomerName] LIKE '%'+@c+'%'
Best Regards,Uri Dimant SQL Server MVP,
http://sqlblog.com/blogs/uri_dimant/
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