mysql數據類型轉換
3 回答
qq_笑_17
TA貢獻1818條經驗 獲得超7個贊
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | 數字轉字符 mysql> SELECT CONCAT ( CAST(1 as char) , '2') AS test; +------+ | test | +------+ | 12 | +------+ 1 row in set (0.00 sec)
mysql> SELECT CONCAT ( Convert(1, char) , '2') AS test; +------+ | test | +------+ | 12 | +------+ 1 row in set (0.00 sec)
字符轉數字 mysql> SELECT CAST('1' as SIGNED) + 100 AS test; +------+ | test | +------+ | 101 | +------+ 1 row in set (0.00 sec)
mysql> SELECT Convert('1' , SIGNED) + 100 AS test; +------+ | test | +------+ | 101 | +------+ 1 row in set (0.00 sec) |
精慕HU
TA貢獻1845條經驗 獲得超8個贊
CONVERT() provides a way to convert data between different character sets. The syntax is:
CONVERT(expr USING transcoding_name)
In MySQL, transcoding names are the same as the corresponding character set names.
Examples:
SELECT CONVERT(_latin1'Müller' USING utf8);
INSERT INTO utf8table (utf8column)
SELECT CONVERT(latin1field USING utf8) FROM latin1table;
CONVERT(... USING ...) is implemented according to the standard SQL specification.
You may also use CAST() to convert a string to a different character set. The syntax is:
CAST(character_string AS character_data_type CHARACTER SET charset_name)
Example:
SELECT CAST(_latin1'test' AS CHAR CHARACTER SET utf8);
If you use CAST() without specifying CHARACTER SET, the resulting character set and collation are defined by the character_set_connection and collation_connection system variables. If you use CAST() with CHARACTER SET X, the resulting character set and collation are X and the default collation of X.
You may not use a COLLATE clause inside a CAST(), but you may use it outside. That is, CAST(... COLLATE ...) is illegal, but CAST(...) COLLATE ... is legal.
Example:
SELECT CAST(_latin1'test' AS CHAR CHARACTER SET utf8) COLLATE utf8_bin;
添加回答
舉報
0/150
提交
取消