MySQL에서 흔히 볼 수 있는 하위 쿼리 문
1. SELECT 옵션
mysql> SELECT * FROM my_copy;
+-------+
| name |
+-------+
| curry |
| curry |
| curry |
| A |
| a |
| A |
| a |
| A |
| a |
| A |
| a |
| A |
| B |
| b |
| a |
| A |
| B |
| b |
| a |
| A |
| B |
| b |
+-------+
22 rows in set (0.65 sec)
mysql> SELECT ALL * FROM my_
+-------+
| name |
+-------+
| curry |
| curry |
| curry |
| A |
| a |
| A |
| a |
| A |
| a |
| A |
| a |
| A |
| B |
| b |
| a |
| A |
| B |
| b |
| a |
| A |
| B |
| b |
+-------+
22 rows in set (0.00 sec)
mysql> SELECT DISTINCT * FROM my_copy;
+-------+
| name |
+-------+
| curry |
| A |
| B |
+-------+
3 rows in set (0.09 sec)
2. 필드 별칭
mysql> SELECT id, name AS , age AS , grade AS
-> FROM student;
+----+--------+------+------+
| id | | | |
+----+--------+------+------+
| 1 | curry | 30 | 3.1 |
| 2 | durant | 29 | 3.4 |
| 3 | Riuo | 27 | 3.6 |
| 4 | harden | 29 | 3.2 |
+----+--------+------+------+
4 rows in set (0.13 sec)
3. 데이터 소스
mysql> SELECT * FROM student;
+----+--------+------+-------+------+------+
| id | name | age | grade | sex | c_id |
+----+--------+------+-------+------+------+
| 1 | curry | 30 | 3.1 | | 1 |
| 2 | durant | 29 | 3.4 | | 1 |
| 3 | Riuo | 27 | 3.6 | | 1 |
| 4 | harden | 29 | 3.2 | | 1 |
+----+--------+------+-------+------+------+
4 rows in set (0.00 sec)
mysql> SELECT * FROM student, my_class;
+----+--------+------+-------+------+------+-------+------+------+
| id | name | age | grade | sex | c_id | grade | room | id |
+----+--------+------+-------+------+------+-------+------+------+
| 1 | curry | 30 | 3.1 | | 1 | 101 | S | 2 |
| 1 | curry | 30 | 3.1 | | 1 | 102 | B | 2 |
| 1 | curry | 30 | 3.1 | | 1 | 103 | D | 2 |
| 2 | durant | 29 | 3.4 | | 1 | 101 | S | 2 |
| 2 | durant | 29 | 3.4 | | 1 | 102 | B | 2 |
| 2 | durant | 29 | 3.4 | | 1 | 103 | D | 2 |
| 3 | Riuo | 27 | 3.6 | | 1 | 101 | S | 2 |
| 3 | Riuo | 27 | 3.6 | | 1 | 102 | B | 2 |
| 3 | Riuo | 27 | 3.6 | | 1 | 103 | D | 2 |
| 4 | harden | 29 | 3.2 | | 1 | 101 | S | 2 |
| 4 | harden | 29 | 3.2 | | 1 | 102 | B | 2 |
| 4 | harden | 29 | 3.2 | | 1 | 103 | D | 2 |
+----+--------+------+-------+------+------+-------+------+------+
12 rows in set (0.00 sec)
mysql> SELECT * FROM (SELECT * FROM student) AS stu;
+----+--------+------+-------+------+------+
| id | name | age | grade | sex | c_id |
+----+--------+------+-------+------+------+
| 1 | curry | 30 | 3.1 | | 1 |
| 2 | durant | 29 | 3.4 | | 1 |
| 3 | Riuo | 27 | 3.6 | | 1 |
| 4 | harden | 29 | 3.2 | | 1 |
+----+--------+------+-------+------+------+
4 rows in set (0.05 sec)
4.WHERE 자구
:> < >= <= <> = like between and in not in
:&& || !
mysql> SELECT * FROM student
-> WHERE id = 2 || id = 3;
+----+--------+------+-------+------+------+
| id | name | age | grade | sex | c_id |
+----+--------+------+-------+------+------+
| 2 | durant | 29 | 3.4 | | 1 |
| 3 | Riuo | 27 | 3.6 | | 1 |
+----+--------+------+-------+------+------+
2 rows in set (0.00 sec)
mysql> SELECT * FROM student
-> WHERE id IN(2,3);
+----+--------+------+-------+------+------+
| id | name | age | grade | sex | c_id |
+----+--------+------+-------+------+------+
| 2 | durant | 29 | 3.4 | | 1 |
| 3 | Riuo | 27 | 3.6 | | 1 |
+----+--------+------+-------+------+------+
2 rows in set (0.00 sec)
mysql> SELECT * FROM student
-> WHERE id BETWEEN 1 AND 3;
+----+--------+------+-------+------+------+
| id | name | age | grade | sex | c_id |
+----+--------+------+-------+------+------+
| 1 | curry | 30 | 3.1 | | 1 |
| 2 | durant | 29 | 3.4 | | 1 |
| 3 | Riuo | 27 | 3.6 | | 1 |
+----+--------+------+-------+------+------+
3 rows in set (0.03 sec)
5.group by 자구
mysql> SELECT * FROM student
-> GROUP BY sex;
+----+-------+------+-------+------+------+
| id | name | age | grade | sex | c_id |
+----+-------+------+-------+------+------+
| 3 | Riuo | 27 | 3.6 | | 1 |
| 1 | curry | 30 | 3.1 | | 1 |
+----+-------+------+-------+------+------+
2 rows in set (0.02 sec)
mysql> SELECT sex, COUNT(*), MAX(age), MIN(age), SUM(age)
-> FROM student
-> GROUP BY sex;
+------+----------+----------+----------+----------+
| sex | COUNT(*) | MAX(age) | MIN(age) | SUM(age) |
+------+----------+----------+----------+----------+
| | 1 | 27 | 27 | 27 |
| | 3 | 30 | 29 | 88 |
+------+----------+----------+----------+----------+
2 rows in set (0.09 sec)
mysql> SELECT sex, COUNT(*)
-> FROM student
-> GROUP BY sex DESC;
+------+----------+
| sex | COUNT(*) |
+------+----------+
| | 3 |
| | 1 |
+------+----------+
2 rows in set (0.00 sec)
mysql> SELECT *, COUNT(*) FROM student
-> GROUP BY grade, sex;
+----+--------+------+-------+------+------+----------+
| id | name | age | grade | sex | c_id | COUNT(*) |
+----+--------+------+-------+------+------+----------+
| 1 | curry | 30 | 3.1 | | 1 | 1 |
| 4 | harden | 29 | 3.2 | | 1 | 1 |
| 2 | durant | 29 | 3.4 | | 1 | 1 |
| 3 | Riuo | 27 | 3.6 | | 1 | 1 |
+----+--------+------+-------+------+------+----------+
4 rows in set (0.00 sec)
mysql> SELECT sex, age, count(*), group_concat(name)
-> FROM student
-> group by sex;
+------+------+----------+---------------------+
| sex | age | count(*) | group_concat(name) |
+------+------+----------+---------------------+
| | 27 | 1 | Riuo |
| | 30 | 3 | curry,durant,harden |
+------+------+----------+---------------------+
2 rows in set (0.06 sec)
mysql> SELECT sex, count(*) FROM student
-> group by sex with rollup;
+------+----------+
| sex | count(*) |
+------+----------+
| | 1 |
| | 3 |
| NULL | 4 |
+------+----------+
3 rows in set (0.00 sec)
mysql> SELECT grade, COUNT(*)
-> FROM student
-> GROUP BY grade
-> HAVING COUNT(*) = 1;
+-------+----------+
| grade | COUNT(*) |
+-------+----------+
| 3.1 | 1 |
| 3.2 | 1 |
| 3.4 | 1 |
| 3.6 | 1 |
+-------+----------+
4 rows in set (0.00 sec)
mysql> SELECT grade, COUNT(*) AS total
-> FROM student
-> GROUP BY grade
-> HAVING total = 1;
+-------+-------+
| grade | total |
+-------+-------+
| 3.1 | 1 |
| 3.2 | 1 |
| 3.4 | 1 |
| 3.6 | 1 |
+-------+-------+
4 rows in set (0.00 sec)
7.order by 자구
mysql> SELECT *
-> FROM student
-> ORDER BY age;
+----+--------+------+-------+------+------+
| id | name | age | grade | sex | c_id |
+----+--------+------+-------+------+------+
| 3 | Riuo | 27 | 3.6 | | 1 |
| 2 | durant | 29 | 3.4 | | 1 |
| 4 | harden | 29 | 3.2 | | 1 |
| 1 | curry | 30 | 3.1 | | 1 |
+----+--------+------+-------+------+------+
4 rows in set (0.00 sec)
mysql> SELECT *
-> FROM student
-> ORDER BY age,grade DESC;
+----+--------+------+-------+------+------+
| id | name | age | grade | sex | c_id |
+----+--------+------+-------+------+------+
| 3 | Riuo | 27 | 3.6 | | 1 |
| 2 | durant | 29 | 3.4 | | 1 |
| 4 | harden | 29 | 3.2 | | 1 |
| 1 | curry | 30 | 3.1 | | 1 |
+----+--------+------+-------+------+------+
4 rows in set (0.00 sec)
8.Limit 자구
mysql> SELECT * FROM student LIMIT 2;
+----+--------+------+-------+------+------+
| id | name | age | grade | sex | c_id |
+----+--------+------+-------+------+------+
| 1 | curry | 30 | 3.1 | | 1 |
| 2 | durant | 29 | 3.4 | | 1 |
+----+--------+------+-------+------+------+
2 rows in set (0.00 sec)
mysql> SELECT * FROM student LIMIT 0, 2;
+----+--------+------+-------+------+------+
| id | name | age | grade | sex | c_id |
+----+--------+------+-------+------+------+
| 1 | curry | 30 | 3.1 | | 1 |
| 2 | durant | 29 | 3.4 | | 1 |
+----+--------+------+-------+------+------+
2 rows in set (0.00 sec)
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