php error happened

Technical information
Error type256
Error descriptionUnknown column 'Class_Instructions' in 'field list'
URLtamisglassartcompany.com/class_schedule_master_list.php?
Error file/var/www/localhost/tamisartglasscompany.com/connections/Connection.php
Error line668
SQL queryselect count(*) from (SELECT `ID`, `Class_ID`, `Class_Name`, `Class_Description`, `Class_Instructions`, `Safety_Instructions`, `Supplies_Required`, `Estimated_Course_Time`, `Instructor_Notes`, `Class_Date`, `Class_Duration`, `Class_Sessions`, `Class_Max_Size`, `Class_Instructor`, `List_Class_Date`, `Show_In_Pased_Classes`, `Instructor_Instructions`, `Class_Cost_Per_Person`, `Class_Picture`, `Class_Picture_TN` FROM `Class_Schedule_Master` WHERE ( ( ( ( `ID` is null ) or ( `ID` > 0 ) or ( `ID`=0 ) or ( `ID` < 0 ) ) ) ) ) a

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