获取列中允许的最大长度，mysql [英] Get the max length allowed in column, mysql

问题描述

我需要知道如何获取mysql中特定列的最大大小，表是

i need to know how to get the max size of an specific column in mysql, the table is

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

`nombreTurno` varchar(20) COLLATE utf8_spanish2_ci NOT NULL

我应该得到：

20

im gets：

NULL

查询：

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

希望你能帮助我，谢谢你

hope you can help me, thank you

推荐答案

select COLUMN_NAME, CHARACTER_MAXIMUM_LENGTH 
from information_schema.columns
where table_schema = DATABASE() AND   -- name of your database
      table_name = 'turno' AND        -- name of your table
      COLUMN_NAME = 'nombreTurno'     -- name of the column

• SQLFiddle演示


• SQLFiddle Demo

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