Here are a couple of ways to check whether or not a key exists in Redis.
Continue readingAuthor: Ian
2 Ways to Return a Random Member from a Redis Set
Redis provides us with two commands that allow us to get one or more random members from a given set – SRANDMEMBER and SPOP.
Actually, the commands are slightly different in that one deletes the random member whereas the other doesn’t, and so the command you choose will depend on whether or not you want to delete the random member at the same time.
Continue readingAdd Hours to a Time Value in SQLite
In SQLite, we can use the TIME() function to add a given number of hours to a time value.
If we’re dealing with datetime values, we can use the DATETIME() function.
Fix: “ERR value is out of range, must be positive” when using SPOP in Redis
If you’re getting an error that reads “ERR value is out of range, must be positive” in Redis, it’s probably because you’re passing a negative count value to the SPOP command.
To fix this issue, make sure the second argument (if supplied) is a positive value.
Continue readingFix: “ERR wrong number of arguments for ‘sismember’ command” in Redis
If you’re getting an error that reads “ERR wrong number of arguments for ‘sismember’ command” in Redis, it’s because you’re calling the SISMEMBER 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 two.
Continue readingRedis SUNIONSTORE Command Explained
In Redis, the SUNIONSTORE command does the same thing that SUNION does, except that it stores the result in a key. More specifically, it takes the members of the set resulting from the union of all of the given sets, and stores them in the specified key.
Redis SUNION Command Explained
In Redis, the SUNION command returns the members of the set resulting from the union of all of the given sets.
5 Ways to Check if a Table has a Generated Column in MariaDB
Here are five ways to see whether a table contains a generated column in MariaDB.
Continue readingRedis SREM Command Explained
In Redis, the SREM command allows us to remove one or more members from a set.
Fix “ERR syntax error” when using the SISINTERCARD Command in Redis
If you’re getting an error that reads “ERR syntax error” when using the SINTERCARD command, it could be because your first argument is too low.
If this is the case, you can easily fix the issue by making sure that the first argument reflects the actual number of sets that you’re comparing.
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