3、ect * from syscolumns where id=object_id('PartStock') and name='PartVelocity') print 'PartVelocityexists'elseprint'PartVelocitynotexists'另法:判断表的存在性: selectcount(*)fromsysobjectswheretype='U'andname='你的表名'判断字段的存在性: selectcount(*
4、)fromsyscolumns whereid =(selectidfromsysobjectswheretype='U'andname='你的表名') and name='你要判断的字段名' 一个小例子--假设要处理的表名为:tb--判断要添加列的表中是否有主键ifexists(select1fromsysobjectswhereparent_obj=object_id('tb')andxtype='PK')beginprint'表中已经有主键,列只能做为普通列添加'--添加int类
8、se。 selecttype,sum(casevenderwhenAthenpcselse0end),sum(casevenderwhenCthenpcselse0end),sum(casevenderwhenBthenpcselse0end)FROMtablenamegroupbytype15.说明:初始化表table1 TRUNCATETABLEtable116.说明:几个高级查询运算词 A