Database Management Systems
If you want to use named time zones in MariaDB, you’ll need to make sure they’ve been configured.
By “named time zones”, I mean being able to use strings like America/Los_Angeles instead of −08:00 or −07:00 when specifying the time zone. For example, when using the CONVERT_TZ() function.
Here’s how to configure named time zones in MariaDB.
Continue readingIf you have documents that store dates as Date objects, but you want to return them in a different format, you can use the $dateToString aggregate pipeline operator.
For example, you might want a date to be returned in mm/dd/yyyy format instead of the long ISODate() format that includes minutes, seconds, milliseconds, etc
The $dateToString operator converts the Date object to a string, and optionally allows you to specify a format for the resulting output.
If you’re getting a “longitude/latitude is out of bounds” error when trying to create a 2dsphere index in MongoDB, it could be due to your longitude and latitude coordinates being in the wrong order.
Continue readingMariaDB provides several ways to add a certain number of days to a given date. For example, you might want to add 10 days to a date, or 30 days, or even just 1 day. Fortunately, MariaDB makes this easy.
Here are 8 ways to add a number of days to a given date in MariaDB.
Continue readingFrom MongoDB 4.4, it’s possible to hide an index from the query planner. This allows you to evaluate the potential impact of dropping an index without actually dropping the index.
You can use the getIndexes() method to check whether or not an index is hidden. If an index is hidden, that index will display a hidden field as having a value of true (i.e. "hidden" : true).
If you’re using a T-SQL function such as OPENJSON(), JSON_QUERY(), or JSON_VALUE(), you might be wary of any non-alphanumeric characters that might be in the JSON document that you’re working with. Especially if those special characters are in the key names, and you need to reference those key names.
In MariaDB, ADDTIME() is a built-in date and time function that adds an amount to a time or datetime expression.
It allows you to change a time or datetime expression by passing that expression, as well as a time expression to add to that expression. You can pass a negative amount if you need to subtract from the time expression.
Continue readingIn MariaDB, SUBTIME() is a built-in date and time function that subtracts an amount from a time or datetime expression.
It allows you to change a time or datetime expression by passing that expression, as well as a time expression to subtract from that expression. You can pass a negative amount if you need to add to the time expression.
Continue readingBelow is a full list of the date and time units that can be used in MariaDB.
Continue readingIn MariaDB, SUBDATE() is a built-in date and time function that subtracts an amount from a given date.
It allows you to change a date by specifying the date, the unit to subtract, and the amount to subtract. You can pass a negative amount in order to add to the date, instead of subtracting from it.
SUBDATE() also has a shortcut syntax that allows you to specify the days to subtract.