There are a couple of commands that enable us to rename a key in Redis. The one we use will depend on whether or not we want to overwrite any existing keys.
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Fix: “ERR syntax error” when using SPOP in Redis
If you’re getting an error that reads “ERR syntax error” in Redis, it could be because you’re calling the SPOP command with too many arguments.
At the time of writing, I find that I only get this argument when I pass too many arguments. If I pass no arguments, I get a different error.
Continue readingHow to Get a Substring in Redis
If we have a key that holds a string value, we can use the GETRANGE command to get a substring from that value.
Redis also has a SUBSTR command that does the same thing, but that was deprecated in Redis 2.0.0, in favour of the GETRANGE command.
How to Copy a Key’s Value to Another Key in Redis
As from Redis 6.2.0, we can use the COPY command whenever we need to copy a key’s value to another key.
Fix: “ERR wrong number of arguments for ‘spop’ command” in Redis
If you’re getting an error that reads “ERR wrong number of arguments for ‘spop’ command” in Redis, it’s because you’re calling the SPOP command with the wrong number of arguments.
At the time of writing, I find that I only get this argument when I pass no arguments. If I pass too many, I get a different error.
In any case, to fix this issue, be sure to pass at least one argument to the command (and at the time of writing, no more than two).
Continue reading2 Ways to Check if a Key Exists in Redis
Here are a couple of ways to check whether or not a key exists in Redis.
Continue reading2 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.
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