错误：列“EP_TEXT”指定了多次

Question

I try to use script to add column to table, no matter i change to which name, it always return error saying

Column names in each table must be unique. Column name 'xxx' in table 'TEST_TABLE' is specified more than once.

I randomly key in a name, it still saying that name is specified more than once. but actually not, there is no such column existed yet, and column finally is not added successfully also.

anyone had any idea? thanks

below is my query:

GO
if not exists(SELECT * FROM INFORMATION_SCHEMA.COLUMNS where TABLE_NAME = 'TEST_TABLE' AND COLUMN_NAME = 'EP_TEXT')
begin 
ALTER TABLE TEST_TABLE ADD EP_TEXT [dbo].[UDDT_MAXVARCHAR] NULL
end 
GO

Answer 1

The problem is that INFORMATION_SCHEMA.TABLE does not have a COLUMN_NAME column. Try this:

IF NOT EXISTS(
     SELECT * from INFORMATION_SCHEMA.TABLES t1
              INNER JOIN INFORMATION_SCHEMA.COLUMNS t2 on t1.TABLE_NAME = t2.TABLE_NAME
              where t1.TABLE_NAME = 'TEST_TABLE' and t2.COLUMN_NAME = 'EP_TEXT'
     )