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This article introduces the relevant knowledge of "how to query the number of fields in mysql". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

Query method: 1, using the description statement to display the table structure, syntax "DESCRIBE table name;", the total number of rows of records output is the number of fields; 2, by using the count () function to count the number of data specified in the system table "information_schema.COLUMNS" to query the number of fields.

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

There are two ways for MySQL to look up the number of fields in a table

Method 1: use the description statement

DESCRIBE displays the field information of the table in the form of a table, including field name, field data type, whether it is a primary key, whether there is a default value, etc. The syntax format is as follows:

DESCRIBE table name

It can be written as follows:

DESC table name

The total number of record rows output is the number of fields.

Example:

Method 2: through the system table information_ schema.`COLUMNS` (supported by mysql5 above)

Query the number of fields by using the count () function to count the number of rows specified in the system table "information_schema.COLUMNS".

Syntax:

SELECT count (1) from information_schema.COLUMNS WHERE table_schema=' library name 'and table_name=' table name'

Table_schema: database name

Table_name: table name

Example:

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