From the JETSQL40.CHM docs: :D
SELECT TOP n [PERCENT] FROM table
TOP n [PERCENT] Returns a certain number of records that fall at the top or the bottom of a range specified by an ORDER BY clause. Suppose you want the names of the top 25 students from the class of 1994:
SELECT TOP 25 FirstName, LastName
FROM Students
WHERE GraduationYear = 1994
ORDER BY GradePointAverage DESC;
If you do not include the ORDER BY clause, the query will return an arbitrary set of 25 records from the Students table that satisfy the WHERE clause.
The TOP predicate does not choose between equal values. In the preceding example, if the twenty-fifth and twenty-sixth highest grade point averages are the same, the query will return 26 records.
You can also use the PERCENT reserved word to return a certain percentage of records that fall at the top or the bottom of a range specified by an ORDER BY clause. Suppose that, instead of the top 25 students, you want the bottom 10 percent of the class:
SELECT TOP 10 PERCENT FirstName, LastName
FROM Students
WHERE GraduationYear = 1994
ORDER BY GradePointAverage ASC;
The ASC predicate specifies a return of bottom values. The value that follows TOP must be an unsigned Integer.
TOP does not affect whether or not the query is updatable.