Top & Limit & Fetch First

💡 Top & Limit & Fetch First

Top은 반환할 레코드 수를 지정하는 데 사용하며, 수천개의 레드코드 있는 대형 테이블에 유용하다.

참고: 모든 DB에서 Select Top을 지원하는 것은 아니다.

 

SQL Server

SELECT TOP number|percent column_name(s)
FROM table_name
WHERE condition;

MySQL

SELECT column_name(s)
FROM table_name
WHERE condition
LIMIT number;

Oracle12

SELECT column_name(s)
FROM table_name
ORDER BY column_name(s)
FETCH FIRST number ROWS ONLY;

---

Sample Table

CustomerID	CustomerName	ContactName	Address	City	PostalCode	Country
1	Alfreds Futterkiste	Maria Anders	Obere Str. 57	Berlin	12209	Germany
2	Ana Trujillo Emparedados y helados	Ana Trujillo	Avda. de la Constitución 2222	México D.F.	05021	Mexico
3	Antonio Moreno Taquería	Antonio Moreno	Mataderos 2312	México D.F.	05023	Mexico
4	Around the Horn	Thomas Hardy	120 Hanover Sq.	London	WA1 1DP	UK
5	Berglunds snabbköp	Christina Berglund	Berguvsvägen 8	Luleå	S-958 22	Sweden

---

예시

처음 3개의 레코드 선택

 

SQL Server

SELECT TOP 3 *
FROM Customers;

MySQL

SELECT *
FROM Customers
LIMIT 3;

Oracle

SELECT *
FROM Customers
FETCH FIRST 3 ROWS ONLY;

---

테이블의 레코드 중 처음 50% 선택

 

SQL Server

SELECT TOP 50 PERCENT * 
FROM Customers;

Oracle

SELECT *
FROM Customers
FETCH FIRST 50
PERCENT ROWS ONLY;

---

국가가 Germany인 처음 3개의 레코드 선택

 

SQL Server

SELECT TOP 3 *
FROM Customers
WHERE Country = 'Germany';

MySQL

SELECT *
FROM Customers
WHERE Country = 'Germany'
LIMIT 3;

Oracle

SELECT *
FROM Customers
WHERE Country = 'Germany'
FETCH FIRST 3 ROWS ONLY;