文字列関数
連結や置換に関する関数
CONCAT()
mysql> SELECT CONCAT(NAME, 'AAA') FROM City LIMIT 1;
+---------------------+
| CONCAT(NAME, 'AAA') |
+---------------------+
| KabulAAA |
+---------------------+
1 row in set (0.02 sec)
CONCAT_WS()
mysql> SELECT CONCAT_WS('---', Name, 'AAA') FROM City LIMIT 1;
+-------------------------------+
| CONCAT_WS('---', Name, 'AAA') |
+-------------------------------+
| Kabul---AAA |
+-------------------------------+
1 row in set (0.00 sec)
INSERT()
mysql> SELECT INSERT(Name, 3, 5, 'what') FROM City LIMIT 1;
+----------------------------+
| INSERT(Name, 3, 5, 'what') |
+----------------------------+
| Kawhat |
+----------------------------+
1 row in set (0.01 sec)
REPLACE()
mysql> SELECT REPLACE(Name, 'bul', 'AAA') FROM City LIMIT 1;
+-----------------------------+
| REPLACE(Name, 'bul', 'AAA') |
+-----------------------------+
| KaAAA |
+-----------------------------+
1 row in set (0.00 sec)
変換関数
LOWER()
mysql> SELECT LOWER(Name) FROM City LIMIT 1;
+-------------+
| LOWER(Name) |
+-------------+
| kabul |
+-------------+
1 row in set (0.00 sec)
UPPER()
mysql> SELECT UPPER(Name) FROM City LIMIT 1;
+-------------+
| UPPER(Name) |
+-------------+
| KABUL |
+-------------+
1 row in set (0.00 sec)
REPEAT()
mysql> SELECT REPEAT(Name, 5) FROM City LIMIT 1;
+---------------------------+
| REPEAT(Name, 5) |
+---------------------------+
| KabulKabulKabulKabulKabul |
+---------------------------+
1 row in set (0.00 sec)
REVERSE()
mysql> SELECT REVERSE(Name) FROM City LIMIT 1;
+---------------+
| REVERSE(Name) |
+---------------+
| lubaK |
+---------------+
1 row in set (0.00 sec)
検索関数
LOCATE(), POSITION(), INSTR()
mysql> SELECT LOCATE('bu', Name) FROM City LIMIT 1;
+--------------------+
| LOCATE('bu', Name) |
+--------------------+
| 3 |
+--------------------+
1 row in set (0.01 sec)
STRCMP()
mysql> SELECT STRCMP('Kebul', Name) FROM City LIMIT 1;
+-----------------------+
| STRCMP('Kebul', Name) |
+-----------------------+
| 1 |
+-----------------------+
1 row in set (0.00 sec)
mysql> SELECT STRCMP('Kabul', Name) FROM City LIMIT 1;
+-----------------------+
| STRCMP('Kabul', Name) |
+-----------------------+
| 0 |
+-----------------------+
1 row in set (0.01 sec)