How to find the length of data in mysql

Mysql method to find the data length: 1. Use the "LENGTH" function to get the string length, with syntax such as "SELECT LENGTH('Character')"; 2. Check the string length through the "CHAR_LENGTH" function, The syntax is "SELECT CHAR_LENGTH('character')".

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MySql calculates the length of the field

User accounts have Chinese characters, find all accounts containing Chinese characters

SELECT member_name FROM table_member WHERE length(member_name)!=char_length(member_name)

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LENGTH

The "LENGTH" function in mysql is a built-in function used to obtain the length of a string

CHAR_LENGTH

View the string in the mysql built-in function There is also a length function called "CHAR_LENGTH". The difference between the two functions is:

LENGTH: A Chinese character counts as three characters, and a number or letter counts as one character.
CHAR_LENGTH: Whether it is Chinese characters, numbers or letters, it is considered a character

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Example

Chinese characters

SELECT LENGTH('字符');
输出：6

SELECT CHAR_LENGTH('字符');
输出：2

Characters

SELECT LENGTH('abc');
输出：3

SELECT CHAR_LENGTH('abc');
输出：3

CommandUnitA Chinese characterA number or letterExampleCharacter11Byte31##bit_lengthlength(str)

char_length				char_length(str)
length				length(str)
bit	24	8

When the length of the string exceeds the maximum length defined by max_allowed_packet, the above function will return NULL .

max_allowed_packet generally defaults to 4MB (1MB for 5.6.5 and below)

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