In SQLite, we can use the TIME() function to add a given number of minutes to a time value.
If we’re dealing with datetime values, we can use the DATETIME() function.
Author: Ian
Fix: “ERR wrong number of arguments for ‘smembers’ command” in Redis
If you’re getting an error that reads “ERR wrong number of arguments for ‘smembers’ command” in Redis, it’s because you’re calling the SMEMBERS command with the wrong number of arguments.
To fix this issue, make sure you’re passing the correct number of arguments. At the time of writing, the correct number of arguments for this command is one.
Continue readingHow to Rename a Key in Redis Without Fear of Overwriting any Existing Keys
If you need to rename a key in Redis, you may be wondering how to do it without overwriting any existing keys. If you use the RENAME command, and a key already exists with your new key name, you’ll overwrite the existing key.
Fortunately, Redis also has a RENAMENX command, which only renames the key if there’s no other key with the new name. So we can use this command whenever we need to rename a key without fear of overwriting any existing keys.
14 Commands that Set Strings in Redis
I thought I’d compile a list of Redis commands that can be used to set strings. Each command has its own specific use, and so the command used will depend on the situation.
In any case, here are 14 commands that set strings in Redis.
Continue readingHow to Return the Definition of a Generated Column in MariaDB
If you have a table in MariaDB with a generated column, you can use the following methods to find out its definition.
Continue reading7 Commands that Get the String Value from a Key in Redis
I decided to compile a list of commands that can be used to get the string value from a key in Redis. These are all string commands – commands that can be used when working with strings. In other words, the assumption is that the key holds a string value.
Continue readingFix “WRONGTYPE Operation against a key holding the wrong kind of value” When Calling SUNION or SUNIONSTORE in Redis
If you’re getting an error that reads “WRONGTYPE Operation against a key holding the wrong kind of value” when calling either the SUNION command or the SUNIONSTORE command in Redis, it’s probably because you’re passing a key with the wrong data type.
To fix this issue, make sure that each key that you pass holds a set.
Continue reading3 Ways to Return all Members of a Set in Redis
When working with Redis, we have multiple ways to return the members of a set. Here are 3 ways to return the members of a set in Redis.
Continue readingHow to Get a Key’s Type in Redis
If you know the name of a key in Redis, but you want to find out it’s type (eg, string, list, hash, set, etc), look no further than the TYPE command. This command returns the string representation of the type of the value at the given key.
How to Return a Random Key in Redis
If you ever find yourself in the situation where you need to get a random key when using Redis, take a look at the RANDOMKEY command.
This command returns a random key from the currently selected database.
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