categories: computer science
Hello everyone,
Below you will find a video with a detailed explanation of the statements and keywords: SELECT, FROM, GROUP BY, SUM, MIN, MAX, AVG, AS, COUNT, i.e. aggregate functions in general. It covers how they work, their time complexity, and their usefulness. Below you will also find ready-to-copy code in case you need it.
Query 1:
SELECT SUM(Srednia) AS Suma
FROM srednia;
Statements: SELECT, SUM, AS, FROM
Query 2:
SELECT klasa
FROM uczniowie
GROUP BY klasa;
Statements: SELECT, GROUP BY, FROM
Query 3:
SELECT klasa, COUNT(klasa) AS Ile
FROM uczniowie
GROUP BY klasa;
Statements: SELECT, COUNT, GROUP BY, AS, FROM
Query 4:
SELECT klasa AS Klasa, COUNT(klasa) AS Ile
FROM uczniowie
GROUP BY klasa
HAVING COUNT(klasa) > 1;
Statements: SELECT, COUNT, GROUP BY, AS, FROM, HAVING
Query 5:
SELECT MAX(Srednia) AS [Max],
MIN(Srednia) AS [Min],
AVG(Srednia) AS [SredniaCalk],
SUM(Srednia) AS [Suma]
FROM srednia;
Statements: SELECT, MAX, MIN, AVG, SUM, AS, FROM
Video:
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