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What is varchar in mysql? Many novices are not very clear about this. In order to help you solve this problem, the following editor will explain it in detail. People with this need can come and learn. I hope you can gain something.

Varchar is a variable-length type in mysql. In a data column of type varchar, each value takes up just enough bytes, plus a byte used to record its length. If the maximum length of a string column is much larger than the average length, you can use varchar to store it.

Varchar Typ

Varchar is a variable-length type: in a data column of type varchar (M), each value occupies just enough bytes, plus a byte used to record its length (that is, the total length is 1 bytes).

When querying, mysql uses a fixed width for the varchar field in memory rather than the variable width when it is stored, especially the invisible temporary table created during the query. Therefore, when selecting field properties, it is enough to choose the most appropriate and minimum length according to your own business, so as to improve the query speed and reduce the overhead of the database server.

When to select the varchar column for storage?

1. The maximum length of a string column is much larger than the average length, giving full play to the characteristics of getting longer.

2. String columns that are rarely updated

Because a storage page of the innodb engine is 16k, frequent updates of variable length fields may lead to the splitting of the storage page, resulting in storage fragmentation.

3. Multi-byte character set, such as utf-8

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