小编use*_*046的帖子

我需要知道如何获取mysql中特定列的最大大小,表是

turno:

CREATE TABLE `turno` (  
`idTurno` tinyint(4) NOT NULL,  
`nombreTurno` varchar(20) COLLATE utf8_spanish2_ci NOT NULL,  
`horaInicio` tinyint(4) NOT NULL,  
`horafin` tinyint(4) NOT NULL,  
`valorTurno` int(11) NOT NULL,  
PRIMARY KEY (`idTurno`)) 
ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_spanish2_ci

专栏:

`nombreTurno` varchar(20) COLLATE utf8_spanish2_ci NOT NULL

我应该得到:

20

我越来越:

NULL

查询:

SELECT MAX( LENGTH( nombreTurno ) ) AS maxl
FROM turno

希望你能帮帮我,谢谢

我收到这个错误:

#1062 - 密钥'PRIMARY'重复输入'127'

而且找不到原因.

查询:

INSERT INTO `portautomadb`.`tag` (`codigo`) VALUES ('00');
INSERT INTO `portautomadb`.`tag` (`codigo`) VALUES ('01'); 
INSERT INTO `portautomadb`.`tag` (`codigo`) VALUES ('02'); 
INSERT INTO `portautomadb`.`tag` (`codigo`) VALUES ('03'); 
INSERT INTO `portautomadb`.`tag` (`codigo`) VALUES ('04'); 
INSERT INTO `portautomadb`.`tag` (`codigo`) VALUES ('05'); 
INSERT INTO `portautomadb`.`tag` (`codigo`) VALUES ('06'); 
INSERT INTO `portautomadb`.`tag` (`codigo`) VALUES ('07'); 
INSERT INTO `portautomadb`.`tag` (`codigo`) VALUES ('08'); 
INSERT INTO `portautomadb`.`tag` (`codigo`) VALUES ('09'); 
INSERT INTO `portautomadb`.`tag` (`codigo`) VALUES ('0A'); 
INSERT INTO `portautomadb`.`tag` (`codigo`) VALUES ('0B'); 
INSERT INTO …