如何在单个查询中读取多个dbf文件

Question

我正在尝试以下查询来读取同一文件夹中的多个dbf文件：

"SELECT COMPNO FROM REF10,REF11,REF12,REF08,REF09 WHERE SR_NO='RDDFT000108'";

以上会产生以下错误：

  

“指定字段'COMPNO'可以引用多个表   列在SQL语句的FROM子句中。“

如何在同一查询中引用多个表？

Answer 1

尝试使用UNION

SELECT COMPNO  FROM REF10 WHERE SR_NO='RDDFT000108';
UNION ALL;
SELECT COMPNO  FROM REF11 WHERE SR_NO='RDDFT000108';
UNION;
SELECT COMPNO  FROM REF12 WHERE SR_NO='RDDFT000108';
UNION;
SELECT COMPNO  FROM REF08 WHERE SR_NO='RDDFT000108';
UNION;
SELECT COMPNO  FROM REF09  WHERE SR_NO='RDDFT000108';

Answer 2

您应该在查询文本中使用表定义：

"SELECT REF10.COMPNO, REF11.COMPNO, REF12.COMPNO, REF08.COMPNO, REF09.COMPNO FROM REF10,REF11,REF12,REF08,REF09 WHERE SR_NO='RDDFT000108'";