SQL语句判断

来源：互联网发布：数据库的测试方法编辑：程序博客网时间：2024/06/07 01:53
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      /// <summary>        /// 判断是否存在某表的某个字段        /// </summary>        /// <param name="tableName">表名称</param>        /// <param name="columnName">列名称</param>        /// <returns>是否存在</returns>        public static bool ColumnExists(string tableName, string columnName)        {            string sql = "select count(1) from syscolumns where [id]=object_id('" + tableName + "') and [name]='" + columnName + "'";            object res = GetSingle(sql);            if (res == null)            {                return false;            }            return Convert.ToInt32(res) > 0;        }//带参数的SQL   /// <summary>        /// 删除        /// </summary>        /// <param name="id"></param>        /// <returns></returns>        public int Delete(int id)        {            string sql = @"DELETE FROM ProjectProcedure WHERE ID=@ID";            SqlParameter[] parameters = new SqlParameter[]{new SqlParameter("@ID", SqlDbType.Int){ Value = id }};            return dbHelper.Execute(sql, parameters);        }创建表之前先判断数据库是否存在该表，如果存在就先删除再创建if exists (select * from sysobjects where name = 'ContractCategory')drop table ContractCategory create table ContractCategory ( ID Int identity(1,1) primary key,-- Name Varchar(50), --类别名称)go
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