My understaind is this error prevents the accidental overwriting of existing columns and maintains integrity of the table's structure.

The error occurs because the sp_rename stored procedure is used to rename a column, but the new name specified ("AccountID") is already an existing column in the table ("AccountID"). The sp_rename procedure doesn't allow renaming a column to a name that already exists in the table.

For example I have Created a table.

CREATE  TABLE MyTable
(
accountid INT,
Name VARCHAR(50),
Balance DECIMAL(10, 2)
)

I have encountred the same error like you have

I have recreated the stored procedure that will rename my Column name with Case sensitive. like below.

CREATE  PROCEDURE dbo.RenameColumns
AS
BEGIN
IF  OBJECT_ID('MyTable', 'U') IS  NOT  NULL
BEGIN
IF  EXISTS (
SELECT  1
FROM sys.columns
WHERE  object_id = OBJECT_ID('MyTable')
AND name = 'AccountId'
)
BEGIN
DECLARE @sql NVARCHAR(MAX);
SET @sql = N'EXEC sp_rename ''MyTable."AccountId"'', ''Account_ID_Renamed'', ''COLUMN'';';
EXEC sp_executesql @sql;
END
ELSE
BEGIN
RAISERROR('Column AccountId does not exist in MyTable.', 16, 1);
END
END
ELSE
BEGIN
RAISERROR('Table MyTable does not exist.', 16, 1);
END
END

In this stored Proc checks if a table named "MyTable" exists in the current database. The 'U' parameter specifies that it should check for user-defined tables. IF EXISTS (SELECT 1 FROM sys.columns WHERE object_id = OBJECT_ID('MyTable') AND name = 'AccountId') This checks if a column named "AccountId" exists in the "MyTable" table.

It queries the sys.columns system catalog view to find the column based on the object_id of the table and the column name.

SET @sql = N'EXEC sp_rename ''MyTable."AccountId"'', ''Account_ID_Renamed'', ''COLUMN''

The Renaming is happening here rename the column "AccountId" to "Account_ID_Renamed" in the "MyTable"

RAISERROR('Table MyTable does not exist.', 16, 1): This line raises an error with the specified message if the "MyTable" table does not exist.

Here Is the other way you can create a New table with new Column name using the stored Procedure that does the New table creation.

CREATE  PROCEDURE dbo.CreateRenamedTable
AS
BEGIN
IF  EXISTS (SELECT  1  FROM sys.tables WHERE name = 'MyTable')
BEGIN
IF  EXISTS (SELECT  1  FROM sys.columns WHERE  object_id = OBJECT_ID('MyTable') AND name = 'Account_ID_Renamed')
BEGIN
CREATE  TABLE dbo.NewTable
(
Account_ID_Renamed_01 INT  -- New column name
);
INSERT  INTO dbo.NewTable (Account_ID_Renamed_01 
SELECT Account_ID_Renamed 
FROM MyTable;
END
ELSE
BEGIN
THROW 50000, 'Column Account_ID_Renamed does not exist in MyTable.', 1;
END
END
ELSE
BEGIN
THROW 50000, 'Table MyTable does not exist.', 1;
END
END