Here are three options for returning the first day of a month in MariaDB.
This could be the first day of the current month, or the first day of the month based on a date that we specify.
Continue readingAuthor: Ian
Redis TYPE Command Explained
In Redis, the TYPE command returns a key’s type. More specifically, it returns the string representation of the type of the value stored at a given key.
Redis UNLINK Command Explained
In Redis, the UNLINK command removes the specified keys. It’s similar to the DEL command, except that it performs the memory reclaiming in a different thread, so it is not blocking. The DEL command, on the other hand, doesn’t do this.
More specifically, the UNLINK command unlinks the keys from the keyspace, and then removes it later asynchronously.
Redis RENAMENX Command Explained
In Redis, the RENAMENX command renames a key, but only if the new key doesn’t already exist.
RENAMENX is similar to the RENAME command, except that it only renames the key if the new one doesn’t already exist. The RENAME command on the other hand, will overwrite the new key if it already exists.
How to Run the Same Command Multiple Times in Redis
The Redis CLI allows us to easily run a command multiple times. All we need to do is prefix the command with the number of times we want it to run.
Continue readingRedis RENAME Command Explained
In Redis, the RENAME command renames a key. It allows us to give a key a new name.
Return Only Numeric Values in SQL
If you ever need to use SQL to return just the numeric values in a character column, the method you use will largely depend on your DBMS. Most DBMSs support regular expressions (regex), but some don’t. And some include functions that can detect numeric values.
Here are examples of how to do it in the more popular DBMSs.
Continue readingRedis COPY Command Explained
In Redis, the COPY command copies the value from one key to another.
This command was introduced in Redis 6.2.0.
Continue readingRedis RESTORE Command Explained
In Redis, the RESTORE command creates a key associated with a value that is obtained by deserialising the provided serialised value (obtained via the DUMP command).
The serialisation format contains a 64-bit checksum, as well as the RDB version. The RESTORE command checks the RDB version and data checksum. If they don’t match an error is returned.
Redis GETRANGE Command Explained
In Redis, the GETRANGE command allows us to get part of a string at a given key, starting and ending at the specified offsets.
The GETRANGE command replaced the SUBSTR command, which basically does the same thing. The SUBSTR command is now considered deprecated (as of Redis 2.0.0).