What is the difference between char and varchar in mysql

Difference: 1. The maximum length of the char field is 255 characters, and the maximum length of the varchar field is 65535 bytes; 2. The char type is wasteful in space usage, while the varchar type is relatively wasteful in space usage. Saving; 3. The search efficiency of char type is high, while the search efficiency of varchar type is relatively low.

The operating environment of this tutorial: windows7 system, mysql8 version, Dell G3 computer.

The difference between char and varchar

##BehaviorMaximum length255 characters 65535 bytes, so the maximum number of characters in brackets must be calculated through encodingIs it a negative lengthFixed length, the insufficient part is filled with hidden spacesVariable lengthSpace usageThere will be wasteMore savings Search efficiencyHighLowTail spaceOmitted when insertingWill not be omitted when inserted , omit like when searching. The ' ' after like in the statement will not be omitted. The ' ' after like in the statement will not be omitted. , the spaces at the end of the field will not be omitted

	charField	varcharField

Summary

• char(n) n in is the number of characters, ranging from 0 to 255 (an additional 1 to 2 bytes are needed to store the length)

• varchar(n) n in is also the number of characters, but the maximum value needs to be calculated through encoding and cannot exceed 65535 bytes (1 to 2 bytes are needed to store the length)

• General Use the char type for fixed-length data, such as ID number, mobile phone number, phone number, etc. If the length changes greatly, you can use the varchar type

• Pay attention to the matching of trailing spaces, especially when inserting And when using like to search

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