blocks|key|833222|text|TINYTEXT:+256字节|type|unstyled|depth|inlineStyleRanges|entityRanges|data|833223|文本:+65,535字节|833224|媒体:+16,777,215字节|833225|LONGTEXT:+4294,967,295字节|833226|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|L|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|M|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

TINYTEXT: 256 bytes 
TEXT: 65,535 bytes 
MEDIUMTEXT: 16,777,215 bytes 
LONGTEXT: 4,294,967,295 bytes

blocks|key|617606|text|根据http://dev.mysql.com/doc/refman/5.0/en/storage-requirements.html的说法，限制是L+%2B+2+bytes,+where+L+<+2%5E16，即64k。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|617607|您不必担心限制它，它会自动分解为随着字符串增长而添加的块，因此它不会总是盲目地使用64k。|617608|entityMap|0|LINK|mutability|MUTABLE|url|http://dev.mysql.com/doc/refman/5.0/en/storage-requirements.html^0|21|R|2|1S|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@$9|S|A|T|1|U]]|E|$]]|$1|F|3|G|5|6|7|V|8|@]|D|@]|E|$]]|$1|H|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]]]

Acording to <a href="http://dev.mysql.com/doc/refman/5.0/en/storage-requirements.html">http://dev.mysql.com/doc/refman/5.0/en/storage-requirements.html</a>, the limit is <code>L + 2 bytes, where L &lt; 2^16</code>, or 64k.

You shouldn't need to concern yourself with limiting it, it's automatically broken down into chunks that get added as the string grows, so it won't always blindly use 64k.

blocks|key|617751|text|TEXT是字符串数据类型，最多可存储65,535个字符。但是，如果您想存储更多数据，请将其数据类型更改为LONGTEXT|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|617752|ALTER+TABLE+name_tabel+CHANGE+text_field+LONGTEXT字符集utf8+COLLATE+utf8_general_ci+NOT+NULL|617753|entityMap^0|0|4|1G|8|0|C|A|U|A|1G|4|1T|F|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|I|$]]

<code>TEXT</code> is a string data type that can store up to 65,535 characters.
But still if you want to store more data then change its data type to <code>LONGTEXT</code>

ALTER TABLE <code>name_tabel</code> CHANGE <code>text_field</code> LONGTEXT CHARACTER SET <code>utf8</code> COLLATE <code>utf8_general_ci</code> NOT NULL;

blocks|key|617862|text|适用于MySql+8.0版。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|617863|数字类型存储要求|617864|Data+Type+++++++Storage+Required
TINYINT+++++++++1+byte
SMALLINT++++++++2+bytes
MEDIUMINT+++++++3+bytes
INT,+INTEGER++++4+bytes
BIGINT++++++++++8+bytes
FLOAT(p)++++++++4+bytes+if+0+<=+p+<=+24,+8+bytes+if+25+<=+p+<=+53
FLOAT+++++++++++4+bytes
DOUBLE,+REAL++++8+bytes
DECIMAL(M,D),+NUMERIC(M,D)++Varies;+see+following+discussion
BIT(M)++approximately+(M%2B7)/8+bytes|code-block|syntax|javascript|617865|十进制(和数字)列的值是使用二进制格式表示的，该格式将九个十进制(以10为基数)的数字打包成四个字节。每个值的整数部分和小数部分的存储分别确定。每九位数的倍数需要四个字节，而“剩余”数字需要四个字节的小数。下表列出了多余数字所需的存储空间。|617866|日期和时间类型存储要求对于TIME、DATETIME和TIMESTAMP列，在MySQL+5.6.4之前创建的表所需的存储空间与从5.6.4开始创建的表不同。这是由于5.6.4中的更改，允许这些类型具有小数部分，这需要0到3个字节。|617867|Data+Type+++Storage+Required+Before+MySQL+5.6.4+++Storage+Required+as+of+MySQL+5.6.4
YEAR++++++++1+byte++++++++++++++++++++++++++++++++1+byte
DATE++++++++3+bytes+++++++++++++++++++++++++++++++3+bytes
TIME++++++++3+bytes+++++++++++++++++++++++++++++++3+bytes+%2B+fractional+seconds+storage
DATETIME++++8+bytes+++++++++++++++++++++++++++++++5+bytes+%2B+fractional+seconds+storage
TIMESTAMP+++4+bytes+++++++++++++++++++++++++++++++4+bytes+%2B+fractional+seconds+storage|617868|从MySQL+5.6.4开始，年份和日期的存储保持不变。但是，时间、日期时间和时间戳的表示方式不同。DATETIME的打包效率更高，非小数部分需要5个字节而不是8个字节，并且所有三个部分都有一个需要0到3个字节的小数部分，具体取决于存储值的小数秒精度。|617869|Fractional+Seconds+Precision++++Storage+Required
0+++++++++++++++++++++++++++++++0+bytes
1,+2++++++++++++++++++++++++++++1+byte
3,+4++++++++++++++++++++++++++++2+bytes
5,+6++++++++++++++++++++++++++++3+bytes|617870|例如，TIME(0)、TIME(2)、TIME(+4+)和TIME(6)分别使用3、4、5和6个字节。时间和时间(0)相等，需要相同的存储空间。|617871|有关时态值的内部表示形式的详细信息，请参见MySQL内部:重要算法和结构。|617872|字符串类型存储要求在下表中，M表示非二进制字符串类型的声明列长度(以字符为单位)和二进制字符串类型的以字节为单位的声明列长度。L表示给定字符串值的实际长度。|617873|Data+Type++++++++++++++++++++Storage+Required
CHAR(M)++++++++++++++++++++++The+compact+family+of+InnoDB+row+formats+optimize+storage+for+variable-length+character+sets.+See+COMPACT+Row+Format+Characteristics.+Otherwise,+M+×+w+bytes,+<=+M+<=+255,+where+w+is+the+number+of+bytes+required+for+the+maximum-length+character+in+the+character+set.
BINARY(M)++++++++++++++++++++M+bytes,+0+<=+M+<=+255
VARCHAR(M),+VARBINARY(M)+++++L+%2B+1+bytes+if+column+values+require+0+−+255+bytes,+L+%2B+2+bytes+if+values+may+require+more+than+255+bytes
TINYBLOB,+TINYTEXT+++++++++++L+%2B+1+bytes,+where+L+<+28
BLOB,+TEXT+++++++++++++++++++L+%2B+2+bytes,+where+L+<+216
MEDIUMBLOB,+MEDIUMTEXT+++++++L+%2B+3+bytes,+where+L+<+224
LONGBLOB,+LONGTEXT+++++++++++L+%2B+4+bytes,+where+L+<+232
ENUM('value1','value2',...)++1+or+2+bytes,+depending+on+the+number+of+enumeration+values+(65,535+values+maximum)
SET('value1','value2',...)+++1,+2,+3,+4,+or+8+bytes,+depending+on+the+number+of+set+members+(64+members+maximum)|617874|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|13|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|14|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|15|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|16|8|@]|9|@]|A|$]]|$1|M|3|N|5|F|7|17|8|@]|9|@]|A|$G|H]]|$1|O|3|P|5|6|7|18|8|@]|9|@]|A|$]]|$1|Q|3|R|5|F|7|19|8|@]|9|@]|A|$G|H]]|$1|S|3|T|5|6|7|1A|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1B|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1C|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|F|7|1D|8|@]|9|@]|A|$G|H]]|$1|10|3|-4|5|6|7|1E|8|@]|9|@]|A|$]]]|11|$]]

For the MySql version 8.0.

<h2>Numeric Type Storage Requirements</h2>

<pre><code>Data Type Storage Required
TINYINT 1 byte
SMALLINT 2 bytes
MEDIUMINT 3 bytes
INT, INTEGER 4 bytes
BIGINT 8 bytes
FLOAT(p) 4 bytes if 0 &lt;= p &lt;= 24, 8 bytes if 25 &lt;= p &lt;= 53
FLOAT 4 bytes
DOUBLE, REAL 8 bytes
DECIMAL(M,D), NUMERIC(M,D) Varies; see following discussion
BIT(M) approximately (M+7)/8 bytes
</code></pre>

Values for DECIMAL (and NUMERIC) columns are represented using a binary format that packs nine decimal (base 10) digits into four bytes. Storage for the integer and fractional parts of each value are determined separately. Each multiple of nine digits requires four bytes, and the “leftover” digits require some fraction of four bytes. The storage required for excess digits is given by the following table.

Date and Time Type Storage Requirements
For TIME, DATETIME, and TIMESTAMP columns, the storage required for tables created before MySQL 5.6.4 differs from tables created from 5.6.4 on. This is due to a change in 5.6.4 that permits these types to have a fractional part, which requires from 0 to 3 bytes.

<pre><code>Data Type Storage Required Before MySQL 5.6.4 Storage Required as of MySQL 5.6.4
YEAR 1 byte 1 byte
DATE 3 bytes 3 bytes
TIME 3 bytes 3 bytes + fractional seconds storage
DATETIME 8 bytes 5 bytes + fractional seconds storage
TIMESTAMP 4 bytes 4 bytes + fractional seconds storage
</code></pre>

As of MySQL 5.6.4, storage for YEAR and DATE remains unchanged. However, TIME, DATETIME, and TIMESTAMP are represented differently. DATETIME is packed more efficiently, requiring 5 rather than 8 bytes for the nonfractional part, and all three parts have a fractional part that requires from 0 to 3 bytes, depending on the fractional seconds precision of stored values.

<pre><code>Fractional Seconds Precision Storage Required
0 0 bytes
1, 2 1 byte
3, 4 2 bytes
5, 6 3 bytes
</code></pre>

For example, TIME(0), TIME(2), TIME(4), and TIME(6) use 3, 4, 5, and 6 bytes, respectively. TIME and TIME(0) are equivalent and require the same storage.

For details about internal representation of temporal values, see MySQL Internals: Important Algorithms and Structures.

String Type Storage Requirements
In the following table, M represents the declared column length in characters for nonbinary string types and bytes for binary string types. L represents the actual length in bytes of a given string value.

<pre><code>Data Type Storage Required
CHAR(M) The compact family of InnoDB row formats optimize storage for variable-length character sets. See COMPACT Row Format Characteristics. Otherwise, M × w bytes, &lt;= M &lt;= 255, where w is the number of bytes required for the maximum-length character in the character set.
BINARY(M) M bytes, 0 &lt;= M &lt;= 255
VARCHAR(M), VARBINARY(M) L + 1 bytes if column values require 0 − 255 bytes, L + 2 bytes if values may require more than 255 bytes
TINYBLOB, TINYTEXT L + 1 bytes, where L &lt; 28
BLOB, TEXT L + 2 bytes, where L &lt; 216
MEDIUMBLOB, MEDIUMTEXT L + 3 bytes, where L &lt; 224
LONGBLOB, LONGTEXT L + 4 bytes, where L &lt; 232
ENUM('value1','value2',...) 1 or 2 bytes, depending on the number of enumeration values (65,535 values maximum)
SET('value1','value2',...) 1, 2, 3, 4, or 8 bytes, depending on the number of set members (64 members maximum)
</code></pre>

I'm creating a form for sending private messages and want to set the <code>maxlength</code> value of a textarea appropriate to the max length of a <code>text</code> field in my MySQL database table. How many characters can a type text field store?

If a lot, would I be able to specify length in the database text type field as I would with varchar?

Maximum length for MySQL type text

我正在创建一个用于发送私人消息的表单，并希望将文本区域的maxlength值设置为与MySQL数据库表中的text字段的最大长度相适应。一个类型的文本字段可以存储多少个字符？如果很多，我是否可以像在varchar中那样在数据库文本类型字段中指定长度？

问MySQL类型文本的最大长度
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回答 4

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