IF EXISTS (SELECT 1 FROM MYTABLE WHERE OBJ_NAME = '[OBJ_NAME]';

IF EXISTS (SELECT 1 FROM MYTABLE WHERE OBJ_NAME = 'OBJ_NAME';

CREATE TABLE TEST
(
    ID     INT IDENTITY(1,1) PRIMARY KEY,
    OBJECT sysname NOT NULL
);
GO

INSERT INTO TEST VALUES ('[obj1]'),('obj2'),('obj3'),('[obj4]');
GO

IF OBJECT_ID('TEST') IS NOT NULL
BEGIN
    SELECT 'TEST EXISTS.' OBJECT_ID;
END
GO

| OBJECT_ID    |
| :----------- |
| TEST EXISTS. |

IF OBJECT_ID('[TEST]') IS NOT NULL
BEGIN
    SELECT '[TEST] EXISTS.' OBJECT_ID;
END
GO

| OBJECT_ID      |
| :------------- |
| [TEST] EXISTS. |

CREATE FUNCTION UNQUOTENAME(@TXT NVARCHAR(MAX))
RETURNS NVARCHAR(MAX)
AS
    BEGIN
        RETURN IIF(LEFT(@TXT, 1) = N'[' AND RIGHT(@TXT, 1) = N']',
                   SUBSTRING(@TXT, 2, LEN(@TXT) -  2),
                   @TXT);
    END;
GO

SELECT dbo.UNQUOTENAME (N'[FIELD]') NAME1, N'FIELD' NAME2;
GO

NAME1 | NAME2
:---- | :----
FIELD | FIELD

SELECT ID, OBJECT
FROM   TEST
WHERE OBJECT LIKE 'obj%';
GO

ID | OBJECT
-: | :-----
 2 | obj2
 3 | obj3

SELECT ID, dbo.UNQUOTENAME(OBJECT)
FROM   TEST
WHERE  dbo.UNQUOTENAME(OBJECT) LIKE 'obj%';
GO

ID | (No column name)
-: | :---------------
 1 | obj1
 2 | obj2
 3 | obj3
 4 | obj4