SETQUOTED_IDENTIFIERON;SETANSI_NULLSON;GOCREATEPROCEDUREp_AlterColumn@TableNameVARCHAR(50),@ColumnNameVARCHAR(50),@ColumnTypeVARCHAR(50),--ModifyFlag='1000'ColumnType='NULL'表示删除@ColumnIsNullVARCHA