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MySQL Articles
Page 3 of 355
How to set delay for MySQL trigger/procedure execution?
When we want to add a pause in MySQL triggers or stored procedures, we use the SLEEP() function. This function stops the execution of a query or procedure for a set amount of time. It is useful in different scenarios such as checking how an app acts when operations slow down or stimulating network slowness. SLEEP() Function MySQL has this SLEEP() function that will suspend the operation for a specified time duration. For example, if you want to pause for 5 seconds, you would write - SLEEP(5); This causes the database to wait for 5 ...
Read MoreEnum with NOT NULL in a MySQL field?
In MySQL, the ENUM is a data type that is used to create a column with a fixed set of values. It is helpful for the fields that have limited alternatives, such as categories, statuses, and color codes. In the ENUM data type, if you do not declare NOT NULL then it gives the default value NULL or Empty String('') when inserting records without specifying a value. However, if you declare NOT NULL and don't specify the values when inserting then it gives the first value from the ENUM. Following is the syntax to create a table that has ...
Read MoreDo MySQL Can Enum type values contain spaces in it?
Yes, you can include a string value with spaces in ENUM type. This is particularly useful when we add descriptive options that contain multiple words. Let us explore how to create, describe, and use ENUM columns containing spaces, with supporting examples. ENUM vs VARCHAR: While both ENUM and VARCHAR can store strings with spaces, ENUM has an advantage: limiting of the number of entries that can be added into a column to a fixed set. Because of this, it is useful in situations where the values are limited and static, such as size categories, and status codes. Whereas VARCHAR is ...
Read MoreDoes SQL Server have an equivalent to MySQL\\\\\\\'s ENUM data type?
No, SQL Server doesn’t offer a direct equivalent to MySQL’s ENUM data type, but you can replicate similar functionality with a combination of VARCHAR, and a CHECK constraint. This allows you to restrict the possible values for a column, just like ENUM does in MySQL. This article will look at how SQL Server can handle ENUM-like behavior and examples of how it is being utilized in your database design. Enum in MySQL In MySQL, the ENUM is a data type that is used to create a column with a fixed set of predefined values which allows data integrity. ...
Read MoreHow can I remove a value from an enum in MySQL?
Removing Value from an enum in MySQL We can use the ALTER command to remove a value from an ENUM in MySQL. The ALTER database command lets you modify the type of a column, add or remove columns, or even modify ENUM values in a current database. You cannot delete a value from an ENUM type. To accomplish that task, you change the column definition - by changing the list of allowed values. This way, the structure of the table is not changed while the set of possible values for the ENUM column is changed. Example Let us first create ...
Read MoreHow can I insert default value in MySQL ENUM data type?
When designing a database, setting default values for certain fields will improve data integrity. In MySQL, ENUM data type allows you to specify predefined values for a column such as status (complete or incomplete). This article helps you to set a default value for ENUM columns, to ensure that even if the data is missing, a suitable value is automatically assigned. Inserting a default value with ENUM data type We can do this with the help of the DEFAULT attribute of the ENUM data type. The DEFAULT attribute causes an ENUM data type to have a default value when a ...
Read MoreCount items in a MySQL table with type ENUM involved?
Counting ENUM items in MySQL In MySQL, ENUM is a data type where it stores the predefined and fixed values making them ideal for categories such as sizes, grades, and statuses. Knowing the frequency of each value inside ENUM columns will allow you to make data-driven decisions. Below, we'll learn how to use MySQL's GROUP BY and COUNT() functions to get the count of ENUM values. GROUP BY(): It is used for aggregating data, as it follows you to perform calculations, such as totals, and averages. ...
Read MoreHow can we create multiple MySQL triggers for the same trigger event and action time?
In MySQL, a trigger is a group of SQL statements performed or fired when a specified event is taken place on tables. The events can include INSERT, UPDATE, and DELETE. Such triggers are used for automating repetitive work, ensuring integrity in data, and keeping audit records without human involvement. The FOLLOWS keyword in MySQL allows the creation of several triggers for the same event and also allows you to select the order of execution. Creating Multiple Triggers for the Same Event When working with triggers, sometimes you might need to define several triggers for the same ...
Read MoreAdd a new value to a column of data type enum in MySQL?
In MySQL, the ENUM is a data type that is used to create a column with a fixed set of values. It is helpful for the fields that have limited alternatives, such as categories, statuses, and color codes. However, as your application evolves, you might need to add more values to the list such as new colors. MySQL allows us to modify ENUM values without dropping and recreating the column. Adding New Value to an ENUM column For adding new values in an ENUM column in MySQL, you shall use the ALTER TABLE command with the MODIFY Keyword. For ...
Read MoreShow MySQL host via SQL Command?
To display MySQL host via SQL command, use the system variable hostname. Query 1 The following is the query to display the host − mysql > select @@hostname; Output Here is the output − +-----------------+ | @@hostname | +-----------------+ | DESKTOP-QN2RB3H | +-----------------+ 1 row in set (0.00 sec) Query 2 Or you can use "show variables" command to show MySQL host via SQL command. show variables where Variable_name like '%host%'; Output The following is the output − +-------------------------------+-----------------+ | Variable_name | Value | +-------------------------------+-----------------+ | host_cache_size | 279 | | hostname | DESKTOP-QN2RB3H | | performance_schema_hosts_size | -1 | | report_host | | +-------------------------------+-----------------+ 4 rows in set (0.07 sec)
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