[SQL] SELECT & FROM & DISTINCT & COUNT & LIMIT

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SQL Übung

• SQL 문법 정리(1)
• SELECTing columns
• COUNT을 통해 행개수 산출

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SELECT & LIMIT

1) SELECTing single column

• Get the title column from the films table.

SELECT name FROM people;

2) SELECTing multiple column

• Get the title and release year from the films table

SELECT title, release_year 
FROM films;

2-2) SELECTing multiple column

• Get all column from the films table

SELECT *
FROM films;

2-3) SELECTing multiple column

• Get all column from the films table but limit the row as 10

SELECT *
FROM films
LIMIT 10;

# from line 8, 2 rows
SELECT *
FROM films
LIMIT 8, 2;

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DISTINCT

3) SELECT DISTINCT

• Get all the unique countries represented in the films table.

SELECT DISTINCT country 
FROM films;

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COUNT

4) COUNT(returns the number of rows in one or more columns)

• Count the number of rows in the people table.

SELECT COUNT(*)
FROM people;

4-2) COUNT(returns the number of rows in one or more columns)

• Count the number of (non-missing) birth dates in the people table.

SELECT COUNT(birthdate)
FROM people;

4-3) COUNT(returns the number of rows in one or more columns)

• Count the number of unique birth dates in the people table.

SELECT COUNT(DISTINCT birthdate)
FROM people;

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