Question

Use EXISTS and select * (anything shows up is good) if it says "there is at least one entry":

Option 1: EXISTS
Option 2: NOT EXISTS
Option 3: ANY
Option 4: ALL

Answer 1

The correct SQL keyword to check for at least one entry in a subquery is EXISTS. It should be used in a WHERE clause and will return true if the subquery has one or more records.

Step-by-step explanation:

The question is asking which SQL keyword should be used to check whether there is at least one entry in a subquery. The correct SQL keyword to use in this case is EXISTS. This keyword is used when you want to check if a subquery returns any results. Using EXISTS will return true if the subquery returns one or more records. Here's an example of how to use EXISTS in a SQL statement:

SELECT * FROM table_name WHERE EXISTS (SELECT * FROM sub_table WHERE condition);

This statement will select all records from table_name where there is at least one entry in sub_table that meets the specified condition.