你可能感興趣的試題

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.

單項選擇題

A SELECT statement can be used to perform these three functions:
1. Choose rows from a table.
2. Choose columns from a table
3. Bring together data that is stored in different tables by creating a link between them.
Which set of keywords describes these capabilities?（）

A. difference, projection, join
B. selection, projection, join
C. selection, intersection, join
D. intersection, projection, join
E. difference, projection, product

You need to calculate the total of all salaries in the accounting department. Which group function should you use?（）

你可能感興趣的試題

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 SELECT statement can be used to perform these three functions: 1. Choose rows from a table. 2. Choose columns from a table 3. Bring together data that is stored in different tables by creating a link between them. Which set of keywords describes these capabilities?（）

A SELECT statement can be used to perform these three functions:
1. Choose rows from a table.
2. Choose columns from a table
3. Bring together data that is stored in different tables by creating a link between them.
Which set of keywords describes these capabilities?（）