单项选择题
In which scenario would index be most useful?（）
A. The indexed column is declared as NOT NULL.
B. The indexed columns are used in the FROM clause.
C. The indexed columns are part of an expression.
D. The indexed column contains a wide range of values.
相关考题
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多项选择题
Which two are true about aggregate functions?（）
A. You can use aggregate functions in any clause of a SELECT statement.
B. You can use aggregate functions only in the column list of the SELECT clause and in the WHERE clause of a SELECT statement.
C. You can mix single row columns with aggregate functions in the column list of a SELECT statement by grouping on the single row columns.
D. You can pass column names, expressions, constants, or functions as parameters to an aggregate function.
E. You can use aggregate functions on a table, only by grouping the whole table as one single group.
F. You cannot group the rows of a table by more than one column while using aggregate functions. -
多项选择题
Which two are attributes of iSQL*Plus? （）
A./SQL*Plus commands cannot be abbreviated.
B./SQL*Plus commands are accessed from a browser.
C./SQL*Plus commands are used to manipulate data in tables.
D./SQL*Plus commands manipulate table definitions in the database.
E./SQL*Plus is the Oracle proprietary interface for executing SQL statements. -
单项选择题
Examine the structure if the EMPLOYEES and NEW EMPLOYEES tables: Which MERGE statement is valid?（）
A.
B.
C.
D.
