While primary keys are generally considered a necessity when it comes to relational databases, they’re usually included in the SQL code that creates the database table.

MySQL 8.0.30 introduced generated invisible primary keys which provide an alternative to explicitly specifying a primary key for a table.

A generated invisible primary key (GIPK) is a primary key that’s created implicitly by the MySQL server. If we create a table without an explicit primary key, the MySQL server automatically creates a generated invisible primary key for us (assuming it’s an InnoDB table and that GIPKs are enabled).

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MySQL has a SHOW CREATE DATABASE statement that shows the CREATE DATABASE statement that would be used to recreate the database.

We can use the SHOW CREATE DATABASE statement to create an identical database on another server, or to create a similar database on the same server (while changing the name).

We can alternatively use SHOW CREATE SCHEMA to do the same thing (SHOW CREATE SCHEMA is a synonym for SHOW CREATE DATABASE).

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In MySQL, we can use the SHOW CREATE TABLE statement to produce a CREATE TABLE statement from an existing table.

This enables us to generate a script that we can use to recreate the table on another database, or on the same database at a later date. Or we could use it to create another similar table. We would need to modify the code accordingly when doing this, but it could give us a good starting point.

We can also use SHOW CREATE TABLE for a quick way to take a look at the table’s structure, and check for things like data types, primary keys, foreign keys, etc.

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MySQL provides the sql_quote_show_create system variable, which allows us to specify whether or not to include quotes around identifiers when using the SHOW CREATE TABLE and SHOW CREATE DATABASE statements.

By default, this variable is set to 1, which means that quotes/backticks will be generated whenever these statements are run.

However, we might not always want quotes or backticks around the object names, and so we can change the value of this variable to disable quoted identifiers.

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In MySQL we can use the DO statement if we want to execute an expression without getting a result set.

DO works in a similar way to the SELECT statement, but without returning a result set like SELECT normally would. DO can also be slightly faster, given it doesn’t return a result set.

This could be useful in stored functions or triggers that don’t allow us to run statements that return a result set.

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In MySQL, we can use the REPLACE statement to insert data if we think that some rows need to replace existing rows.

The REPLACE statement works just like the INSERT statement, except that if it contains rows with the same PRIMARY KEY or UNIQUE index as those in the table, then it replaces those rows in the table. It does this by deleting the old row and then inserting the new row.

To use the REPLACE statement, we must have both the INSERT and DELETE privileges for the table.

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MySQL 8.0.32 introduced the explain_format system variable, which can be used to provide a default output format when using the EXPLAIN statement, or its synonyms DESCRIBE and DESC.

More specifically, it determines the default output format used by this statement in the absence of a FORMAT option when displaying a query execution plan.

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MySQL 8.3 introduced the explain_json_format_version system variable that allows us to specify which JSON output format should be used when we use the EXPLAIN statement with FORMAT=JSON.

It also applies when we omit the FORMAT argument and the explain_format system variable is set to JSON (because explain_format specifies the default format to be used by EXPLAIN).

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In MySQL we can use the EXPLAIN statement to get information about SQL queries that we run against the database. We can also get information about tables and views.

EXPLAIN is a synonym for DESCRIBE (and its short form DESC). Even though these statements all work exactly the same, there’s a common convention amongst MySQL developers to use DESCRIBE for certain tasks and EXPLAIN for others. Typically, DESCRIBE is often used to get information about tables and views, whereas EXPLAIN is used to get information about queries, such as query execution plans.

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