MySQL, ORACLE, SQL SERVER 检查并删除表的方法

MySQL:
DROP TABLE IF EXISTS [table_name]

Oracle:
BEGIN
    EXECUTE IMMEDIATE 'DROP TABLE [table_name]';
    EXCEPTION WHEN OTHERS THEN NULL;
END;

SQL Server:
IF EXISTS (
    SELECT  TABLE_NAME FROM INFORMATION_SCHEMA.TABLES
    WHERE   TABLE_NAME = '[table_name]')
DROP TABLE  [table_name]