- Question: What will happen (assuming permissions are fine and storage is in place)?
BEGIN;
CREATE TABLESPACE myspace LOCATION 'data';
Possible answers:
- It works
- It will error out
- It will issue a warning
Source: http://www.cybertec.at/en/quiz/
- Question: What is the correct result?
SELECT 3 = ALL ('{}'::int[]);
Possible answers:
- NULL
- False
- True
Source: http://www.cybertec.at/en/quiz/
- Question: What is the correct result?
SELECT 3 = ANY ('{}'::int[]);
Possible answers:
- False
- True
- NULL
Source: http://www.cybertec.at/en/quiz/
- Question: What is the correct result?
SELECT NULL IS NULL IS NULL;
Possible answers:
- True
- False
- NULL
Source: http://www.cybertec.at/en/quiz/
- Question: now() can be used to determine transaction time. But what happens in a subtransaction?
BEGIN;
SELECT now();
SAVEPOINT a;
SELECT now();
Possible answers:
- different results
- an error will happen
- same result
Source: http://www.cybertec.at/en/quiz/
- Question: What will happen?
BEGIN;
SAVEPOINT a;
CREATE TABLE x (x int);
SAVEPOINT a;
ROLLBACK TO SAVEPOINT a;
Is there a table there or not?
Possible answers:
- yes, it is there
- no, it is not there
- this one will error out
Source: http://www.cybertec.at/en/quiz/
- Question: Which column are you going to get?
BEGIN;
CREATE TABLE x (x int);
CREATE TEMP TABLE x (y int);
SELECT * FROM x;
Possible answers:
- This will error out all
- The "temporary table" will be shown
- The "real table" will be shown
Source: http://www.cybertec.at/en/quiz/
- Question: What will be the answer?
SELECT COUNT(*)
FROM (VALUES (1), (2)) t ( v )
WHERE v NOT IN (3, 4, NULL);
Possible answers:
- 0
- NULL
- 2
Source: http://www.cybertec.at/en/quiz/
- Question: How many rows will the SELECT return?
CREATE TABLE x (id int);
INSERT INTO x VALUES (0), (NULL);
SELECT * FROM x WHERE id <> 0;
Possible answers:
- 1
- 2
- 0
Source: http://www.cybertec.at/en/quiz/
- Question: What is the correct answer?
SELECT COUNT(DISTINCT t)
FROM (VALUES (1), (2), (NULL), (NULL)) t ( v );
Possible answers:
- 3
- 4
- 2
Source: http://www.cybertec.at/en/quiz/
- Question: What is the correct answer?
SELECT COUNT(v)
FROM (VALUES (1), (2), (NULL), (NULL)) t ( v );
Possible answers:
- 2
- 3
- 4
Source: @NikolayS
- Question: What is the correct answer?
SELECT COUNT(t)
FROM (VALUES (1), (2), (NULL), (NULL)) t ( v );
Possible answers:
- This will error out
- 4
- 2
Source: @NikolayS