How to Hide a GIPK from the SHOW CREATE TABLE Statement (and SHOW COLUMNS and SHOW INDEX) in MySQL

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When we have a table with a generated invisible primary key (GIPK) in MySQL, we can usually see its definition when we use various SHOW statements such as SHOW CREATE TABLE, SHOW COLUMNS, and SHOW INDEX, as well as when we query information schema tables such as information_schema.columns.

But there is a way of hiding the GIPK from such statements. It all comes down to the show_gipk_in_create_table_and_information_schema variable. Yes, there’s actually a system variable that allows us to hide GIPKs from the output of various SHOW statements and information schema tables.

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A Quick Intro to SHOW INDEX in MySQL

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In MySQL we can use the SHOW INDEX statement to return information about the indexes on a table.

We specify which table to show indexes from, and we can optionally specify which database. We can also use a WHERE clause to filter by various criteria.

We can run it against any table where we have some privilege for any column in the table.

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5 Ways to Find a Table’s Primary Key in MySQL

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Generally speaking, most tables we create in MySQL should have a primary key. A primary key is one or more columns that have been configured as the unique identifier for the table.

We usually create the primary key when creating the table, but we can also add a primary key to an existing table (assuming it doesn’t already have one).

Occasionally it might not be immediately apparent which column is the primary key for a given table. Or it might not be apparent whether or not the table has a composite primary key. Fortunately it’s easy enough to find out.

Below are five ways to get the primary key column/s from an existing table in MySQL.

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A Quick Overview of the ‘show_gipk_in_create_table_and_information_schema’ System Variable in MySQL

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Depending on our configuration, if we create a table without a primary key column, MySQL will automatically create one behind the scenes. This is called a generated invisible primary key (GIPK).

We can normally use statements such as SHOW CREATE TABLE, SHOW COLUMNS, SHOW INDEX or even check the information schema to see if a table has a GIPK.

But this depends on the setting of our show_gipk_in_create_table_and_information_schema system variable.

This variable can be set to ON or OFF. When set to ON, we will see GIPKs in the output of the aforementioned statements. When set to OFF, we won’t see any GIPKs.

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Understanding MySQL’s ‘sql_generate_invisible_primary_key’ System Variable

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One of the more recent additions to MySQL’s list of system variables is the sql_generate_invisible_primary_key variable. This variable was introduced in MySQL 8.0.30 along with the introduction of generated invisible primary keys (GIPKs).

The purpose of this variable is to allow us to specify whether or not the system will generate a GIPK when we omit a primary key from a table’s definition when creating the table.

By default the sql_generate_invisible_primary_key is set to OFF, which basically means that GIPKs are disabled by default. But we can change this to ON in order to enable GIPKs.

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