Here are five ways to see whether a table contains a generated column in MariaDB.
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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.
Continue readingFix: “ERR Number of keys can’t be greater than number of args” when using the SINTERCARD Command in Redis
If you’re getting an error that reads “ERR Number of keys can’t be greater than number of args” when using the SINTERCARD command, it’s probably because your first argument is the wrong value.
To fix this issue, make sure the first argument reflects the number of sets that you’re comparing.
Continue readingAdd a Virtual Column to an Existing Table in Oracle
If we need to add a virtual column to an existing table in Oracle Database, we can do so with the usual SQL ALTER TABLE statement.
Fix “ERR wrong number of arguments for ‘sintercard’ command” in Redis
If you’re getting an error that reads “ERR wrong number of arguments for ‘sintercard’ command” in Redis, it’s because you’re calling the SINTERCARD command with the wrong number of arguments.
To fix this issue, make sure you’re passing the correct number of arguments.
Continue readingHow to Convert to Lowercase in MariaDB
In MariaDB, we can use the LOWER() function to convert uppercase characters to their lowercase equivalent.
We can alternatively use LCASE(), which is a synonym of LOWER().
How to Set an Expiry Only When the New Expiry is Less Than the Existing Expiry in Redis
When setting a timeout on a key in Redis, we have the option of setting the timeout only if it’s less than the existing timeout. We can do this with the LT option of commands such as EXPIRE, EXPIREAT, PEXPIRE, and PEXPIREAT.
Subtract Seconds from a Time Value in PostgreSQL
In PostgreSQL, we can use the - operator to subtract one or more seconds from a time value.
By “time” value, this could be an actual time value, a timestamp, or an interval. We can also subtract seconds from a date value or a date and time combination.
How to Return a Key’s Value and Set its Expiry in a Single Operation in Redis
In Redis, typically when we want to return a key’s value, we use the GET command. But there’s also a GETEX command (introduced in Redis 6.2.0) that allows us to get the value and return it’s expiry at the same time.
5 Ways to See if a Table has a Generated Column in MySQL
MySQL supports generated columns. If you’re not sure whether a table has a generated column or not, you can check it using any of the following methods.
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