insert into backupStudent(已存在的表_被插) select * from student (主插)
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select * into backupStudent(目标——不存的表,临时建) from student(来源)
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insert into student(目标) 列名 select '值' union
insert into student(目标) 列名 valuse(cl,c2);insert into student(目标) 列名 valuse(cl,c2);insert into student(目标) 列名 valuse(cl,c2);..