열 유형과 제약 조건

SQL을 활용한 탐색적 데이터 분석

Christina Maimone

Data Scientist

열 제약 조건

일반

특수

Table of numeric data type names and descriptions

Fortune 500 databse table

형식

-- With the CAST function
SELECT CAST (value AS new_type);

예시

-- Cast 3.7 as an integer
SELECT CAST (3.7 AS integer);

-- Cast a column called total as an integer
SELECT CAST (total AS integer)
  FROM prices;

형식

-- With :: notation
SELECT value::new_type;

예시

-- Cast 3.7 as an integer
SELECT 3.7::integer;

-- Cast a column called total as an integer
SELECT total::integer
  FROM prices;

SQL을 활용한 탐색적 데이터 분석