SQL IF ELSE

DECLARE @FCompanyID INT 
SET @FCompanyID=36052

DECLARE @userName VARCHAR(38)
SET @userName='f004'


DECLARE @t_Accounts TABLE
(
    FID INT,
    FAccount VARCHAR(38),
    FCompanyId INT
)

IF (@userName IS NULL OR @userName = '')
BEGIN
    INSERT @t_Accounts ( FID, FAccount, FCompanyId )
    SELECT FID,FAccount,FCompanyID
    FROM dbo.TAccounts
    WHERE FCompanyID=@FCompanyID
END 
ELSE
BEGIN
    INSERT @t_Accounts ( FID, FAccount, FCompanyId )
    SELECT FID,FAccount,FCompanyID
    FROM dbo.TAccounts
    WHERE FCompanyID=@FCompanyID
    AND FAccount=@userName
END 


SELECT * FROM @t_Accounts

 

 

 

DECLARE @FCompanyID INT 
SET @FCompanyID=36052

DECLARE @userName VARCHAR(38)
SET @userName='f004'


SELECT FID,FAccount,FCompanyID
FROM dbo.TAccounts
WHERE FCompanyID=ISNULL(@FCompanyID,FCompanyID)
AND FAccount=ISNULL(@userName,FAccount)