Динамический запрос в SQL сервере

Question

CREATE PROC [dbo].[GetSimExpiryDate] 
    (@val varchar(5)) 
AS 
BEGIN 
    IF(@val ='1') 
    BEGIN 
     (SELECT 
      WS.WSRecordId, WS.SIMNumber, 
      BES.DisplayName, 
      BES.PIN, BES.BESSqlServer, 
      CONVERT(VARCHAR(11), WS.ExpiryDate, 106) as ExpiryDate 
     FROM 
      WEBSERVICE_CACHE AS WS 
     LEFT OUTER JOIN 
      BES_SERVER_CACHE AS BES ON WS.SIMNumber = LEFT(BES.ICCID, 19) 
     WHERE 
      CONVERT(DATETIME, GETDATE(), 109) > CONVERT(DATETIME, WS.ExpiryDate, 109)) 
    END 
    ELSE IF(@val ='2') 
    BEGIN 
     (SELECT 
      WS.WSRecordId, WS.SIMNumber, 
      BES.DisplayName, 
      BES.PIN, BES.BESSqlServer, 
      CONVERT(VARCHAR(11), WS.ExpiryDate, 106) as ExpiryDate  
     FROM 
      WEBSERVICE_CACHE AS WS 
     LEFT OUTER JOIN 
      BES_SERVER_CACHE AS BES ON WS.SIMNumber = LEFT(BES.ICCID,19) 
     WHERE 
      MONTH(WS.ExpiryDate) = MONTH(GETDATE()) 
      AND YEAR(WS.ExpiryDate) = YEAR(GETDATE()) 
      AND CONVERT(DATETIME, GETDATE(), 109) <= CONVERT(DATETIME, WS.ExpiryDate, 109)) 
END 

У меня есть хранимая процедура, которая имеет, если и остальные блоки на основе параметра, переданном в процедуре

В обеих запросах весь код такой же, за исключением того, где положение, как удалить это избыточность. Поскольку у меня есть много elseif

Answer 1

да, вы можете сделать его динамичным. Вы должны использовать sp_Executesql

Пример

/* This stored procedure builds dynamic SQL and executes 
using sp_executesql */ 
Create Procedure sp_EmployeeSelect 
    /* Input Parameters */ 
    @EmployeeName NVarchar(100), 
    @Department NVarchar(50), 
    @Designation NVarchar(50), 
    @StartDate DateTime, 
    @EndDate DateTime, 
    @Salary Decimal(10,2) 

AS 
    Set NoCount ON 
    /* Variable Declaration */ 
    Declare @SQLQuery AS NVarchar(4000) 
    Declare @ParamDefinition AS NVarchar(2000) 
    /* Build the Transact-SQL String with the input parameters */ 
    Set @SQLQuery = 'Select * From tblEmployees where (1=1) ' 
    /* check for the condition and build the WHERE clause accordingly */ 
    If @EmployeeName Is Not Null 
     Set @SQLQuery = @SQLQuery + ' And (EmployeeName = @EmployeeName)' 

    If @Department Is Not Null 
     Set @SQLQuery = @SQLQuery + ' And (Department = @Department)' 

    If @Designation Is Not Null 
     Set @SQLQuery = @SQLQuery + ' And (Designation = @Designation)' 

    If @Salary Is Not Null 
     Set @SQLQuery = @SQLQuery + ' And (Salary >= @Salary)' 

    If (@StartDate Is Not Null) AND (@EndDate Is Not Null) 
     Set @SQLQuery = @SQLQuery + ' And (JoiningDate 
     BETWEEN @StartDate AND @EndDate)' 
    /* Specify Parameter Format for all input parameters included 
    in the stmt */ 
    Set @ParamDefinition =  ' @EmployeeName NVarchar(100), 
       @Department NVarchar(50), 
       @Designation NVarchar(50), 
       @StartDate DateTime, 
       @EndDate DateTime, 
       @Salary Decimal(10,2)' 
    /* Execute the Transact-SQL String with all parameter value's 
     Using sp_executesql Command */ 
    Execute sp_Executesql  @SQLQuery, 
       @ParamDefinition, 
       @EmployeeName, 
       @Department, 
       @Designation, 
       @StartDate, 
       @EndDate, 
       @Salary 

    If @@ERROR <> 0 GoTo ErrorHandler 
    Set NoCount OFF 
    Return(0) 

ErrorHandler: 
    Return(@@ERROR) 
GO 

Для далее here