设有如下关系表R、S和T:R(BH,XM,XB,
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参考答案:
SELECT * FROM R UNION SELECT * FROM T 或 SELE * FROM R UNIO SELE * FROM T 或 SELECT * FROM R UNIO SELECT * FROM T 或 SELE * FROM R UNION SELE * FROM T
\r\n\r\n