SQL operators

Specifies the columns to retrieve in the query.

SELECT clause

Specifies any conditions for the query

WHERE clause

Specifies that all simple conditions must be true for the compound condition to be true

AND operator

Specifies that the compound condition is true whenever any of the simple conditions is true.

OR operator

Reverses the truth or falsity of the orginal condition

NOT operator

Finds rows that do not contain a null value in the specified column

IS NOT NULL operator

Finds rows that contain a null value in the specified column

IS NULL operator

Calculates the average value in a numeric range

AVG function

Specifies a range of values in a condition

BETWEEN operator

Counts the number of rows in a table

COUNT function

Sorts the query results in descending order based on the column name

DESC operator

Indicates the table from which to reetrieve the specified columns

FROM clause

Groups rows based on the specified column

GROUB BY clause

Limits a condition to the groups that are included

HAVING clause

Uses the IN operator to find a value in a group of values specified in the condition

IN clause

Indicates a pattern of characters to find in a condition

LIKE operator

Calculates the maximum value in a numeric range

MAX function

Calculates the minimum value in a numberic range

MIN function

Lists the query results in the specified order based on the column name

ORDER BY clause

Totals the values in a numeric range

SUM function

How do you form a compound condition?

combine simple conditions and using the operators AND, OR, or NOT

How do you use a computed column in SQL? How do you name the computed column?

use arithmetic operators and write the computation in place of a column name. assign a name to the computation by following the computation with the word AS and then the desired name.

What wildcards are available in Oracle, and what do they represent?

In Oracle, the percent (%) wildcard represents any collection of characters. The underscore (_) wildcard represens any single character.

How do you sort data?

ORDER BY clause

How do you sort data in descending order?

follow the sort key with the DESC operator

How do you avoid including duplicate values in a query's results?

precede the column name with the DISTINCE operator

How do you group data in an SQL query?


How do you find rows in which a particular column contains a null value?

IS NULL operator in the WHERE clause

what is it called when one query is inside another query?