SQL

Online Tutorials

WHERE

SELECT name, wins
FROM golfers
WHERE wins = 1;

-- Comparison
SELECT name
FROM golfers
WHERE name = 'George';
-- <>: tests whether two values are not equal
SELECT name, wins
FROM golfers
WHERE wins <> 1;
--
SELECT name, wins
FROM golfers
WHERE wins < 1;
-- <=: tests whether the first value is less than or equal to the second
SELECT name, wins
FROM golfers
WHERE wins <= 1;
-- >=: tests whether the first value is greater than or equal to the second
SELECT name, wins
FROM golfers
WHERE wins >= 1;

-- Null
SELECT name, rounds_played
FROM golfers
WHERE rounds_played IS NULL;

-- Range
SELECT name, best
FROM golfers
WHERE best BETWEEN 67 AND 73;

-- Membership
SELECT name, best
FROM golfers
WHERE best IN (65, 67, 69, 71);

-- Pattern Match
-- _: an underscore represents a single unknown character
SELECT name, rounds_played
FROM golfers
WHERE rounds_played LIKE '2_';
-- %: a percentage sign represents zero or more unknown characters
SELECT name, rounds_played
FROM golfers
WHERE name LIKE 'G%';

-- Combining Multiple Predicates with AND and OR
SELECT name, best, worst, average
FROM golfers
WHERE best < 70 AND worst < 96;
--
SELECT name, best, worst, average
FROM golfers
WHERE best < 70 OR worst < 96;
--
SELECT name, average, worst, rounds_played
FROM golfers
WHERE average < 85 OR worst < 95 AND rounds_played BETWEEN 19 AND 23;
--
SELECT name, average, worst, rounds_played
FROM golfers
WHERE (average < 85 OR worst < 95) AND rounds_played BETWEEN 19 AND 23;

-- Excluding Results with NOT
SELECT name
FROM golfers
WHERE name NOT LIKE 'R%';
--
SELECT name, rounds_played
FROM golfers
WHERE rounds_played IS NOT NULL;
--
SELECT name, average, best, wins
FROM golfers
WHERE NOT (average < 80 AND best < 70) OR wins = 9;
--
SELECT name, average, best, wins
FROM golfers
WHERE NOT ((average < 80 AND best < 70) OR wins = 9);
--
SELECT name
FROM golfers
WHERE name NOT = 'Grady';