올바른 테이블 찾기

실전 문제에 SQL 적용하기

Dmitriy (Dima) Gorenshteyn

Lead Data Scientist, Memorial Sloan Kettering Cancer Center

복잡한 칠판을 바라보는 당황한 남성

어떤 테이블을 써야 하나요?

테이블에 어떤 열이 있나요?
각 열에는 어떤 내용이 있나요?

SELECT * 
FROM payment;

결과를 LIMIT로 줄이기

SELECT * 
FROM payment;

rental_id rental_date       inventory_id customer_id return_date
2         2005-05-24 22:54:33    1525    459         2005-05-28 19:40:33
3         2005-05-24 23:03:39    1711    408         2005-06-01 22:12:39
4         2005-05-24 23:04:41    2452    333         2005-06-03 01:43:41
5         2005-05-24 23:05:21    2079    222         2005-06-02 04:33:21
6         2005-05-24 23:08:07    2792    549         2005-05-27 01:32:07
7         2005-05-24 23:11:53    3995    269         2005-05-29 20:34:53
8         2005-05-24 23:31:46    2346    239         2005-05-27 23:33:46
...................16035 MORE ROWS......................................

결과를 LIMIT로 줄이기

SELECT * 
FROM payment
LIMIT 5;

rental_id rental_date       inventory_id customer_id return_date
2         2005-05-24 22:54:33    1525    459         2005-05-28 19:40:33
3         2005-05-24 23:03:39    1711    408         2005-06-01 22:12:39
4         2005-05-24 23:04:41    2452    333         2005-06-03 01:43:41
5         2005-05-24 23:05:21    2079    222         2005-06-02 04:33:21

내 데이터베이스에는 어떤 테이블이 있나요?

PostgreSQL:

SELECT * 
FROM pg_catalog.pg_tables
;

schemaname     tablename     tableowner 
public         address       postgres
public         actor         postgres
public         film_actor    postgres
public         language      postgres 
...            ...           ...

내 데이터베이스에는 어떤 테이블이 있나요?

PostgreSQL:

SELECT * 
FROM pg_catalog.pg_tables
WHERE schema_name = 'public;

schemaname     tablename     tableowner 
public         address       postgres
public         actor         postgres
public         film_actor    postgres
public         language      postgres
...            ...           ...

내 데이터베이스에는 어떤 테이블이 있나요?

PostgreSQL:

SELECT * FROM pg_catalog.pg_tables;

SQL Server - TSQL:

SELECT * FROM INFORMATION_SCHEMA.TABLES;

MySQL:

SHOW TABLES;

...

필요한 테이블을 찾으세요!

실전 문제에 SQL 적용하기