How To Avoid ELSE-IF Statement In Stored Procedure In SQL Server

In this blog you will learn how to avoid ELSE-IF Statement in stored procedure in SQL Server.

Introduction

In this article we will discuss about how to avoid ELSE-IF Statement in stored procedure in SQL Server. As we all know that stored procedure is faster than LINQ, so we will fetch data from database using stored procedure.

Background

Here we have to use condition with where clause instance of ELSE-IF Statement in stored procedure. Consider we will fetch Unit Price and Current Stock of values from InvStockMaster table in Database by @CompanyID,@DepartmentID, @ItemID, @GradeID and Other Condition we will fetch same values from Same table and Database by @CompanyID, @ItemID, @DepartmentID, @SupplierID, @BatchID,@GradeID,@LotID. Now firstly we will use ELSE-IF Statement and secondly we will avoid ELSE-IF Statement in stored procedure.

Let’s go for it.

Step 1

Right button click on Databases and Click New Database and give database named InventoryDB. Below is the following picture.


Fig: Create Database

OR below is the following query,

CREATE DATABASE InventoryDB;

Step 2

Now we will create table named InvStockMaster.

Right button click on Tables and click New and once Click Table… Below is the following picture.


Fig: InvStockMaster

OR below is the following query,

CREATE TABLE [dbo].[InvStockMaster](
    [StockID] [int] IDENTITY(1,1) NOT NULL,
    [SupplierID] [int] NULL,
    [ItemID] [bigint] NOT NULL,
    [ItemTypeID] [int] NULL,
    [LotID] [bigint] NULL,
    [GradeID] [int] NULL,
    [BatchID] [bigint] NULL,
    [UOMID] [int] NOT NULL,
    [ReceiveQty] [decimal](18, 6) NULL,
    [ReceiveValue] [decimal](18, 0) NULL,
    [LastReceiveDate] [datetime] NULL,
    [IssueQty] [decimal](18, 6) NOT NULL,
    [IssueValue] [decimal](18, 6) NULL,
    [LastIssueDate] [datetime] NULL,
    [CurrentRate] [decimal](18, 6) NOT NULL,
    [CurrentStock]  AS ([ReceiveQty]-[IssueQty]),
    [CurrentValue]  AS ([ReceiveValue]-[IssueValue]),
    [SalesRate] [decimal](18, 6) NOT NULL,
    [SalesValue] [decimal](18, 6) NOT NULL,
    [LastSalesDate] [datetime] NULL,
    [IsActive] [bit] NULL,
    [CompanyID] [int] NULL,
    [DepartmentID] [int] NOT NULL,
 CONSTRAINT [PK_InvStockMaster] PRIMARY KEY CLUSTERED
(
    [StockID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

Our Database and Table have been created so we will add some demo data for getting results  after executing stored procedure.

Here is some demo Data.

GO
INSERT [dbo].[InvStockMaster] ([StockID], [SupplierID], [ItemID], [ItemTypeID], [LotID], [GradeID], [BatchID], [UOMID], [ReceiveQty], [ReceiveValue], [LastReceiveDate], [IssueQty], [IssueValue], [LastIssueDate], [CurrentRate], [SalesRate], [SalesValue], [LastSalesDate], [IsActive], [CompanyID], [DepartmentID]) VALUES (1, 222, 7478, 1, 0, 1, 0, 3, CAST(1000.000000 AS Decimal(18, 6)), CAST(10000 AS Decimal(18, 0)), CAST(N'2016-09-19 17:02:22.820' AS DateTime), CAST(10.000000 AS Decimal(18, 6)), CAST(100.000000 AS Decimal(18, 6)), CAST(N'2016-10-05 00:00:00.000' AS DateTime), CAST(10.000000 AS Decimal(18, 6)), CAST(0.000000 AS Decimal(18, 6)), CAST(0.000000 AS Decimal(18, 6)), NULL, 1, 1, 10)
GO
INSERT [dbo].[InvStockMaster] ([StockID], [SupplierID], [ItemID], [ItemTypeID], [LotID], [GradeID], [BatchID], [UOMID], [ReceiveQty], [ReceiveValue], [LastReceiveDate], [IssueQty], [IssueValue], [LastIssueDate], [CurrentRate], [SalesRate], [SalesValue], [LastSalesDate], [IsActive], [CompanyID], [DepartmentID]) VALUES (2, 225, 7475, 1, 6, 0, 15, 3, CAST(54000.000000 AS Decimal(18, 6)), CAST(54000 AS Decimal(18, 0)), CAST(N'2016-09-20 10:36:55.440' AS DateTime), CAST(10.000000 AS Decimal(18, 6)), CAST(100.000000 AS Decimal(18, 6)), CAST(N'2016-10-05 00:00:00.000' AS DateTime), CAST(10.000000 AS Decimal(18, 6)), CAST(0.000000 AS Decimal(18, 6)), CAST(0.000000 AS Decimal(18, 6)), NULL, 1, 1, 10)
GO
INSERT [dbo].[InvStockMaster] ([StockID], [SupplierID], [ItemID], [ItemTypeID], [LotID], [GradeID], [BatchID], [UOMID], [ReceiveQty], [ReceiveValue], [LastReceiveDate], [IssueQty], [IssueValue], [LastIssueDate], [CurrentRate], [SalesRate], [SalesValue], [LastSalesDate], [IsActive], [CompanyID], [DepartmentID]) VALUES (3, 984, 7481, 4, 12, 0, 10, 3, CAST(1000.000000 AS Decimal(18, 6)), CAST(10000 AS Decimal(18, 0)), CAST(N'2016-09-20 00:00:00.000' AS DateTime), CAST(10.000000 AS Decimal(18, 6)), CAST(100.000000 AS Decimal(18, 6)), CAST(N'2016-10-05 00:00:00.000' AS DateTime), CAST(10.000000 AS Decimal(18, 6)), CAST(0.000000 AS Decimal(18, 6)), CAST(0.000000 AS Decimal(18, 6)), NULL, 1, 1, 10)
GO

Now we will create Stored procedure using ELSE IF Statement.

USE [InventoryDB]
GO
/****** Object:  StoredProcedure [dbo].[Get_LSCurrentStock]    Script Date: 10/14/2016 2:36:14 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:      <Author,,Name>
-- Create date: <Create Date,,>
-- Description: <Description,,>
-- =============================================
--EXEC [Get_LSCurrentStock] 1,7474,10,0,0,0,0
Create PROCEDURE [dbo].[Get_LSCurrentStockWithELSEIF]

     @CompanyID         INT=0
    ,@ItemID            BIGINT=0
    ,@DepartmentID      INT=0
    ,@SupplierID        BIGINT=0
    ,@BatchID           INT=0
    ,@GradeID           INT=0
    ,@LotID             INT=0
AS
BEGIN


          IF(@CompanyID!=0 AND @ItemID!=0 AND @DepartmentID!=0 AND @SupplierID!=0 AND @BatchID!=0 AND @LotID!=0)
          BEGIN
                SELECT TOP 1 ISNULL(ItemID,0) ItemID, ISNULL(CurrentRate,0) UnitPrice, ISNULL(CurrentStock,0) CurrentStock
                from InvStockMaster
                WHERE ItemID=@ItemID AND  DepartmentID=@DepartmentID AND CompanyID=@CompanyID
                AND BatchID=@BatchID AND SupplierID=@SupplierID AND LotID=@LotID
           END

           ELSE IF(@CompanyID!=0 AND @ItemID!=0 AND @DepartmentID!=0 AND @GradeID!=0)
           BEGIN

           SELECT TOP 1 ISNULL(ItemID,0) ItemID, ISNULL(CurrentRate,0) UnitPrice, ISNULL(CurrentStock,0) CurrentStock
                from InvStockMaster
                WHERE ItemID=@ItemID AND  DepartmentID=@DepartmentID AND CompanyID=@CompanyID
                AND GradeID=@GradeID
           END

    END

In the above code we can see that there are code repeats. It’s not good. In this scenario the question arises, what is code repeating?

In software engineering, don't repeat yourself (DRY) is a principle of software development

Let's go for code explanation.

In the above codes we can see that we have used ELSE-IF statements which are some condition.

IF(@CompanyID!=0 AND @ItemID!=0 AND @DepartmentID!=0 AND @SupplierID!=0 AND @BatchID!=0 AND @LotID!=0)
BEGIN
END
ELSE IF(@CompanyID!=0 AND @ItemID!=0 AND @DepartmentID!=0 AND @GradeID!=0)
BEGIN

And we have Selected ItemID,UnitPrice and CurrentStock with some condition with Where clause.

SELECT TOP 1 ISNULL(ItemID,0) ItemID, ISNULL(CurrentRate,0) UnitPrice, ISNULL(CurrentStock,0) CurrentStock
from InvStockMaster
WHERE ItemID=@ItemID AND DepartmentID=@DepartmentID AND CompanyID=@CompanyID
AND BatchID=@BatchID AND SupplierID=@SupplierID AND LotID=@LotID

Finally we will create Store procedure without ELSE-IF Statement.

USE [InventoryDB]
GO
/****** Object:  StoredProcedure [dbo].[Get_LSCurrentStock]    Script Date: 10/14/2016 2:36:14 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:      <Author,,Name>
-- Create date: <Create Date,,>
-- Description: <Description,,>
-- =============================================

Create PROCEDURE [dbo].[Get_LSCurrentStock]

     @CompanyID         INT=0
    ,@ItemID            BIGINT=0
    ,@DepartmentID      INT=0
    ,@SupplierID               BIGINT=0
    ,@BatchID           INT=0
    ,@GradeID           INT=0
    ,@LotID                    INT=0
AS
BEGIN
            SELECT TOP 1 ISNULL(ItemID,0) ItemID, ISNULL(CurrentRate,0) UnitPrice, ISNULL(CurrentStock,0) CurrentStock
            from InvStockMaster
            WHERE ItemID=@ItemID AND  DepartmentID=@DepartmentID AND CompanyID=@CompanyID

            And Convert(varchar, BatchID) Like Case When @BatchID = 0 Then '%' Else CONVERT(varchar, @BatchID) End
            And Convert(varchar, SupplierID) Like Case When @SupplierID = 0 Then '%' Else CONVERT(varchar, @SupplierID) End
            And Convert(varchar, GradeID) Like Case When @GradeID = 0 Then '%' Else CONVERT(varchar, @GradeID) End
           And Convert(varchar, LotID) Like Case When @LotID = 0 Then '%' Else CONVERT(varchar, @LotID) End
    END

Let’s go for code explanation.

SELECT TOP 1 ISNULL(ItemID,0) ItemID, ISNULL(CurrentRate,0) UnitPrice, ISNULL(CurrentStock,0) CurrentStock
from InvStockMaster

Above codes are just Select query.

WHERE ItemID=@ItemID AND DepartmentID=@DepartmentID AND CompanyID=@CompanyID
And Convert(varchar, BatchID) Like Case When @BatchID = 0 Then '%' Else CONVERT(varchar, @BatchID) End
And Convert(varchar, SupplierID) Like Case When @SupplierID = 0 Then '%' Else CONVERT(varchar, @SupplierID) End
And Convert(varchar, GradeID) Like Case When @GradeID = 0 Then '%' Else CONVERT(varchar, @GradeID) End
And Convert(varchar, LotID) Like Case When @LotID = 0 Then '%' Else CONVERT(varchar, @LotID) End

Here we have used Convert, Like and Case Statement

Convert

The CONVERT() function is a general function that converts an expression of one data type to another.

Ex Convert(varchar, BatchID)

Like

The LIKE operator is used to search for a specified pattern in a column.

Ex Like Case When @BatchID = 0 Then '%' Else CONVERT(varchar, @BatchID) End

Case Statement

The CASE statement has the functionality of an IF-THEN-ELSE statement. You can use the CASE statement within a SQL statement.

Ex Case When @BatchID = 0 Then '%' Else CONVERT(varchar, @BatchID) End

Conclusion

Code repeat is problem in software engineering. In this article we have learned how to avoid code repeat and always we will try to avoid using ELSE-IF Statement.