多选题Which two statements are true regarding subqueries? （）AA subquery can retrieve zero or more rowsBOnly two subqueries can be placed atone levelCA subquery can be used only in SQL query statementsDA subquery can appear on either side of a comparison operatorEThere is no limit on the number of subquery levels in the WHERE clause of a SELECT statement
多选题
Which two statements are true regarding subqueries? （）
A
A subquery can retrieve zero or more rows
B
Only two subqueries can be placed atone level
C
A subquery can be used only in SQL query statements
D
A subquery can appear on either side of a comparison operator
E
There is no limit on the number of subquery levels in the WHERE clause of a SELECT statement
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Which two statements about subqueries are true?（）A、A single row subquery can retrieve data from only one table.B、A SQL query statement cannot display data from table B that is referred to in its subquery, unless table B is included in the main query's FROM clause.C、A SQL query statement can display data from table B that is referred to in its subquery, without including table B in its own FROM clause.D、A single row subquery can retrieve data from more than one table.E、A single row subquery cannot be used in a condition where the LIKE operator is used for comparison.F、A multiple-row subquery cannot be used in a condition where the LIKE operator is used for comparison.
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单选题Which best describes an inline view?（）Aa schema objectBa subquery that can contain an ORDER BY clauseCanother name for a view that contains group functionsDa subquery that is part of the FROM clause of another query
多选题Which three statements about subqueries are true?（）AA single row subquery can retrieve only one column and one row.BA single row subquery can retrieve only one row but many columns.CA multiple row subquery can retrieve multiple rows and multiple columns.DA multiple row subquery can be compared by using the “” operator.EA single row subquery can use the IN operator.FA multiple row subquery can use the “=” operator.
多选题Which three statements about subqueries are true? （）AA main query can have more than one subquery.BA subquery can have more than one main query.CThe subquery and main query must retrieve data from the same table.DThe subquery and main query can retrieve data from different tables.EOnly one column or expression can be compared between the subquery and main query.FMultiple columns or expression can be compared between the subquery and main query.
多选题Which two statements are true regarding the USING and ON clauses in table joins?（）ABoth USING and ON clauses can be used for equijoins and nonequijoinsBAmaximum of one pair of columns can be joined between two tables using the ON clauseCThe ON clause can be used to join tables on columns that have different names but compatible data typesDThe WHERE clause can be used to apply additional conditions in SELECT statements containing the ON or the USING clause
多选题Which two statements about subqueries are true? （）AA single row subquery can retrieve data from only one table.BA SQL query statement cannot display data from table B that is referred to in its subquery, unless table B is included in the main query's FROM clause.CA SQL query statement can display data from table B that is referred to in its subquery, without including table B in its own FROM clause.DA single row subquery can retrieve data from more than one table.EA single row subquery cannot be used in a condition where the LIKE operator is used for comparison.FA multiple-row subquery cannot be used in a condition where the LIKE operator is used for comparison.
多选题Which two statements regarding a SQL profile are true？（）AIt is built by Automatic Tuning Optimizer.BIt cannot be stored persistently in the data dictionary.CIt can be used by the query optimizer automatically.DIt can be created manually by using the CREATE PROFILE command.
多选题Which two statements are true about WHERE and HAVING clauses? （）AA WHERE clause can be used to restrict both rows and groups.BA WHERE clause can be used to restrict rows only.CA HAVING clause can be used to restrict both rows and groups.DA HAVING clause can be used to restrict groups only.EA WHERE clause CANNOT be used in a query of the query uses a HAVING clause.FA HAVING clause CANNOT be used in subqueries.
多选题Which two statements about subqueries are true? （）AA single row subquery can retrieve data from only one table.BA SQL query statement cannot display data from table B that is referred to in its subquery, unless table B is included in the main query's FROM clause.CA SQL query statement can display data from table B that is referred to in its subquery, without including B in its own FROM clause.DA single row subquery can retrieve data from more than one table.EA single row subquery cannot be used in a condition where the LIKE operator is used for comparison.FA multiple-row subquery cannot be used in an INSERT statement to insert multiple rows at a time.
多选题Which two statements about subqueries are true? （）AA subquery should retrieve only one row.BA subquery can retrieve zero or more rows.CA subquery can be used only in SQL query statements.DSubqueries CANNOT be nested by more than two levels.EA subquery CANNOT be used in an SQL query statement that uses group functions.FWhen a subquery is used with an inequality comparison operator in the outer SQL statement, the column list in the SELECT clause of the subquery should contain only one column.
多选题Which two statements are true regarding views?（）AA subquery that defines a view cannot include the GROUP BY clauseBA view that is created with the subquery having the DISTINCT keyword can be updatedCA view that is created with the subquery having the pseudo column ROWNUM keyword cannot be updatedDA data manipulation language (DML) operation can be performed on a view that is created with the subquery having all the NOT NULL columns of a table
多选题Which three statements are true regarding subqueries?（）ASubqueries can contain GROUP BY and ORDER BY clausesBMain query and subquery can get data from different tablesCMain query and subquery must get data from the same tablesDSubqueries can contain ORDER BY but not the GROUP BY clauseEOnly one column or expression can be compared between the main query and subqueryFMultiple columns or expressions can be compared between the main query and subquery