5.13. SQL Select Where¶
Order clauses to filter out the most data first!
5.13.1. Selection¶
=
- equals!=
- not equal<>
- not equal>
- greater then>=
- greater or equal<
- less than<=
- less or equal
SELECT *
FROM astronauts
WHERE lastname = 'Watney';
SELECT *
FROM astronauts
WHERE agency != 'NASA';
SELECT *
FROM astronauts
WHERE age > 30;
5.13.2. Conjunction¶
AND
- conjunction
SELECT *
FROM astronauts
WHERE lastname = 'Watney'
AND lastname = 'Mark';
SELECT *
FROM astronauts
WHERE age > 30
AND age < 55;
5.13.3. Alternative¶
OR
- alternative
SELECT *
FROM astronauts
WHERE lastname = 'Watney'
OR lastname = 'Lewis';
5.13.4. Contains¶
IN
- containsNOT IN
- not contains
SELECT *
FROM astronauts
WHERE career IN ('Pilot', 'Engineer', 'Scientist', 'Medical Doctor');
SELECT *
FROM astronauts
WHERE lastname NOT IN ('Watney', 'Lewis', 'Martinez');
5.13.5. Identity¶
IS
- identity checkIS NOT
- negation of an identity check
SELECT *
FROM astronauts
WHERE mission IS NULL;
SELECT *
FROM astronauts
WHERE mission IS NOT NULL;
5.13.6. Like¶
LIKE
%
- Any character (many)_
- Any character (one)
SELECT *
FROM astronauts
WHERE lastname LIKE 'Wat%';
SELECT *
FROM astronauts
WHERE lastname LIKE '%ney';
SELECT *
FROM astronauts
WHERE lastname LIKE '%tn%';
SELECT *
FROM astronauts
WHERE lastname LIKE 'Watne_';
SELECT *
FROM astronauts
WHERE lastname LIKE '_tn%';