A stock exchange needs extremely low latency in their disk subsystem. Which disk storage technology is mostlikely to fulfill their need?()
当前盘当前日录下有数据库db—stock,其中有数据库表stock.dbf,将stock表的股票名称字段的宽度由 8改为10. 应使用sQL语句( )。A.ALTER TABLE stock股票名称 WITHc (10)B.ALTER TABLE stock股票名称c(10)C.ALTER TABLE stock ALTER股票名称c(10)D.ALTER stock ALTER股票名称c(1 0)
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有如下SQL SELECT 语句SELECT * FROM stock WHERE 单价 BETWEEN 12.76 AND 15.20与该语句等价的是A) SELECT * FROM stock WHERE 单价=12.76B) SELECT * FROM stock WHERE 单价12.76C) SELECT * FROM stock WHERE 单价>=15.20.AND.单价15.20.AND.单价<12.76
在当前盘当前目录下删除表stock的命令是A)DROP stock B)DELETE TABLE stockC)DROP TABLE stock D)DELETE stock
将stock表的股票名称字段的宽度由8改为10,应使用SQL语句A) ALTER TABLE stock 股票名称 WITH c(10)B) ALTER TABLE stock 股票名称c(10)C) ALTER TABLE stock ALTER 股票名称c(10)D) ALTER stock ALTER 股票名称c(10)
执行如下SQL语句后SELECT DISTINCT 单价 FROM stock;WHERE 单价=(SELECT min(单价)FROM stock)INTO DBF stock_x表stock_x中的记录个数是A)1 B)2 C)3 D)4
求每个交易所的平均单价的SQL语句是A)SELECT交易所,avg(单价)FROM stock GRDER BY单价B)SELECT交易所,avg(单价)FROM stock ORDER BY单价C)SELECT交易所,avg(单价)FROM stock ORDER BY交易所D)SELECT交易所,avg(单价)FROM stock GROUP BY交易所
Visual FoxPro有如下数据库表stock.dbf,是7月30日沪深股市的收盘情况,请根据此表,完成下题:将stock表中增加一个新字段“交易量”,字段类型是数值型,宽度为8,应使用SQL语句( )。A. ALTER stock ALTER交易量N(8)B. ALTER TABLE stock交易量N(8)C. ALTER TABLE stock ADD交易量N(8)D. ALTER TABLE stock交易量WTIH N(8)