| The SAS data set WORK.CHECK has a variable named Id_Code in it. Which SQL statement would create an index on this variable? A.create index Id_Code on WORK.CHECK; B.create index(Id_Code) on WORK.CHECK; C.make index=Id_Code from WORK.CHECK; D.define index(Id_Code) in WORK.CHECK; 关于在SQL语句中创建INDEX的语句格式如下: 本文属于博客:http://crackman.net/版权归作者所有,欢迎转载!如有转载, 请务必注明出处!未经本文作者同意不得用于商业应用。 General form, CREATE INDEX statement: CREATE <UNIQUE> INDEX index-name ON table-name (column-name-1<, ...column-name-n>); 括号内的语句是可选语句。 答案选A。 示例程序1: data crackman; input id_code name $@; datalines; 1 java 2 c++ 3 dephi 4 asp 5 c#.net ; proc sql; create index id_code on work.crackman; quit; 运行之后看LOG提示。 示例程序2: proc sql; create index id_code on work.crackman(id_code); quit; 示例程序3: proc sql; create index crack on work.check; quit; 示例程序4: data crackman; input id_code name $@; datalines; 1 java 2 c++ 3 dephi 4 asp 4 c#.net ; proc sql; create unqiue index crack on work.check; quit; 分别运行这四个程序,得到LOG提示,看看差别在什么地方? |





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