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多选题
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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更多 “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.” 相关考题
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You define a multiple－row subquery in the WHERE clause of an SQL query with a comparison operator "=". What happens when the main query is executed? ()
A. The main query executes with the first value returned by the subquery.B. The main query executes with the last value returned by the subquery.C. The main query executes with all the values returned by the subquery.D. The main query fails because the multiple-row subquery cannot be used with the comparison operator.E. You cannot define a multiple-row subquery in the WHERE clause of a SQL query.
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Examine the data from the ORDERS and CUSTOMERS tables.Evaluate the SQL statement:What is the result when the query is executed?()
A.B.C.D. The query fails because the subquery returns more than one row.E. The query fails because the outer query and the inner query are using different tables.
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Exhibit:Examine the data in the EMPLOYEES table.Examine the subquery:SELECT last_nameFROM employeesWHERE salary IN (SELECT MAX(salary)FROM employeesGROUP BY department_id);Which statement is true?()
A. The SELECT statement is syntactically accurate.B. The SELECT statement does not work because there is no HAVING clause.C. The SELECT statement does not work because the column specified in the GROUP BY clause is not in the SELECT list.D. The SELECT statement does not work because the GROUP BY clause should be in the main query and not in the subquery.
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Which three statements are true regarding subqueries?（）A、Subqueries can contain GROUP BY and ORDER BY clauses B、Main query and subquery can get data from different tables C、Main query and subquery must get data from the same tables D、Subqueries can contain ORDER BY but not the GROUP BY clause E、Only one column or expression can be compared between the main query and subqueryF、 Multiple columns or expressions can be compared between the main query and subquery
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Which two statements are true regarding views?（）A、A subquery that defines a view cannot include the GROUP BY clause B、A view that is created with the subquery having the DISTINCT keyword can be updated C、A view that is created with the subquery having the pseudo column ROWNUM keyword cannot be updated D、A 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
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Which two statements about subqueries are true? （）A、A subquery should retrieve only one row.B、A subquery can retrieve zero or more rows.C、A subquery can be used only in SQL query statements.D、Subqueries CANNOT be nested by more than two levels.E、A subquery CANNOT be used in an SQL query statement that uses group functions.F、When 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.
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Which three statements about subqueries are true? （）A、A main query can have more than one subquery.B、A subquery can have more than one main query.C、The subquery and main query must retrieve data from the same table.D、The subquery and main query can retrieve data from different tables.E、Only one column or expression can be compared between the subquery and main query.F、Multiple columns or expression can be compared between the subquery and main query.
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Which three statements about subqueries are true?（）A、A single row subquery can retrieve only one column and one row.B、A single row subquery can retrieve only one row but many columns.C、A multiple row subquery can retrieve multiple rows and multiple columns.D、A multiple row subquery can be compared by using the "" operator.E、A single row subquery can use the IN operator.F、A multiple row subquery can use the "=" operator.
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You define a multiple-row subquery in the WHERE clause of an SQL query with a comparison operator "=". What happens when the main query is executed? （）A、The main query executes with the first value returned by the subquery.B、The main query executes with the last value returned by the subquery.C、The main query executes with all the values returned by the subquery.D、The main query fails because the multiple-row subquery cannot be used with the comparison operator.E、You cannot define a multiple-row subquery in the WHERE clause of a SQL query.
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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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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 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 an INSERT statement to insert multiple rows at a time.
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Which two statements about Flashback Query are true？（）A、It is generated by using the redo log files. B、It helps in row-level recovery from user errors.C、It can be performed to recover ALTER TABLE statements D、It fails when undo data pertaining to the transaction is overwritten.E、The database has to be opened with the resetlogs option after performing Flashback Query.
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Which two statements are true regarding single row functions?（）A、They accept only a single argument B、They can be nested only to two levels C、Arguments can only be column values or constants D、They always return a single result row for every row of a queried table E、They can return a data type value different from the one that is referenced
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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.
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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
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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.
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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.
考题
单选题You define a multiple-row subquery in the WHERE clause of an SQL query with a comparison operator "=".What happens when the main query is executed?（）A
The main query executes with the first value returned by the subquery.B
The main query executes with the last value returned by the subquery.C
The main query executes with all the values returned by the subquery.D
The main query fails because the multiple-row subquery cannot be used with the comparison operator.E
You cannot define a multiple-row subquery in the WHERE clause of a SQL query.
考题
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.
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多选题Which three are true? （）AA MERGE statement is used to merge the data of one table with data from another.BA MERGE statement replaces the data of one table with that of another.CA MERGE statement can be used to insert new rows into a table.DA MERGE statement can be used to update existing rows in a table.
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单选题EXHIBIT, Emp Table Exhibit A Exhibit B Examine the data from the EMP table. Evaluate this SQL statement: SELECT * FROM emp WHERE emp _ id = 3); WHERE commission = (SELECT commission FROM emp What is the result when the query is executed?（）A
Exhibit AB
Exhibit BC
The query returns no rowsD
The query fails because the outer query is retrieving more than one columnE
The query fails because both the inner and outer queries are retrieving data from the same table.
考题
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.
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多选题Which two statements about Flashback Query are true？（）AIt is generated by using the redo log files.BIt helps in row-level recovery from user errors.CIt can be performed to recover ALTER TABLE statementsDIt fails when undo data pertaining to the transaction is overwritten.EThe database has to be opened with the resetlogs option after performing Flashback Query.
考题
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
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多选题Which two statements are true regarding single row functions?（）AThey accept only a single argumentBThey can be nested only to two levelsCArguments can only be column values or constantsDThey always return a single result row for every row of a queried tableEThey can return a data type value different from the one that is referenced
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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
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单选题Exhibit: Examine the data in the EMPLOYEES table. Examine the subquery: SELECT last_name FROM employees WHERE salary IN (SELECT MAX(salary) FROM employees GROUP BY department_id); Which statement is true?（）A
The SELECT statement is syntactically accurate.B
The SELECT statement does not work because there is no HAVING clause.C
The SELECT statement does not work because the column specified in the GROUP BY clause is not in the SELECT list.D
The SELECT statement does not work because the GROUP BY clause should be in the main query and not in the subquery.
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