If you’re getting an error that reads “ERR numkeys should be greater than 0” in Redis, it’s probably because you’re specifying a wrong value for the first argument when calling the SINTERCARD command.
To fix this issue, make sure you’re passing a valid non-zero value that matches the number of keys you’re comparing.
Continue readingProbably the most common way of creating a table in SQL is to use a basic CREATE TABLE statement, along with the table’s definition. But that’s not the only way of doing it.
Below are five options for creating a table when using SQL.
Continue readingWe can use the SQL INSERT statement to insert a row into a table. We can also use it to insert more than one row.
Below are seven ways to insert multiple rows into a table in SQL. Most of these examples should work in the major RDBMSs, with the possible exception of Oracle. But no worries, I’ve included an example just for Oracle.
Continue readingIf you’re getting an error that reads “One or more scores can’t be converted into double” when using either the SORT or SORT_RO commands in Redis, it could be because you omitted the ALPHA modifier when trying to sort string values.
If you want to sort string values lexicographically, you need to use the ALPHA modifier when using the SORT or SORT_RO command.
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.
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 readingIf 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.
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 readingIf you have a table in MariaDB with a generated column, you can use the following methods to find out its definition.
Continue readingI 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 reading