修改数据表添加列时先检查列是否存在

IF not exists(SELECT * FROM INFORMATION_SCHEMA.COLUMNS where table_name = 'System_ReportTool_Columns' and column_name = 'sRTC_Like' )BEGINALTER TABLE System_ReportTool_Columns ADD sRTC_Like VARCHAR(50);print'sRTC_Like added.'ENDelse PRINT 'sRTC_Like exists.'