SELECT * statement returns all columns from the provided table in the result set. The given query will fetch all columns and records (rows) from the
Columns or tables in SQL can be aliased using the
AS clause. This allows columns or tables to be specifically renamed in the returned result set. The given query will return a result set with the column for
name renamed to
Unique values of a column can be selected using a
DISTINCT query. For a table
contact_details having five rows in which the
city column contains Chicago, Madison, Boston, Madison, and Denver, the given query would return:
WHERE clause is used to filter records (rows) that match a certain condition. The given query will select all records where the
LIKE operator can be used inside of a
WHERE clause to match a specified pattern. The given query will match any movie that begins with
Star in its title.
_ wildcard can be used in a
LIKE operator pattern to match any single unspecified character. The given query will match any movie which begins with a single character, followed by
% wildcard can be used in a
LIKE operator pattern to match zero or more unspecified character(s). The example query will match any movie that begins with
The, followed by zero or more of any characters.
Column values in SQL records can be
NULL, or have no value. These records can be matched (or not matched) using the
IS NULL and
IS NOT NULL operators in combination with the
WHERE clause. The given query will match all addresses where the address has a value or is not
BETWEEN operator can be used to filter by a range of values. The range of values can be text, numbers or date data. The given query will match any movie made between the years 1980 and 1990, inclusive.
AND operator allows multiple conditions to be combined. Records must match both conditions that are joined by
AND to be included in the result set. The example query will match any car that is blue and made after 2014.
OR operator allows multiple conditions to be combined. Records matching either condition joined by the
OR are included in the result set. The given query will match customers whose state is either
ORDER BY Clause
ORDER BY clause can be used to sort the result set by a particular column either alphabetically or numerically. It can be ordered in ascending (default) or descending order with
DESC. In the example, all the rows of the
contacts table will be ordered by the
birth_date column in descending order.
LIMIT clause is used to narrow, or limit, a result set to the specified number of rows. The given query will limit the result set to 5 rows.