How to query the number of fields by mysql

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:

That's all for the content of "how to query the number of fields in mysql". Thank you for reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!