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.
Author: Ian
Redis SMISMEMBER Command Explained
In Redis, we can use the SMISMEMBER command to find out whether one or more members are in a given set. It’s similar to the SISMEMBER command, except that it allows us to check more than one member at a time.
The SMISMEMBER command was introduced in Redis 6.2.0.
Redis SISMEMBER Command Explained
In Redis, we can use the SISMEMBER command to find out whether or not a set contains a given member.
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 readingRedis SINTERCARD Command Explained
In Redis, the SINTERCARD command returns the cardinality of the set which would result from the intersection of all the given sets. It’s similar to SINTER, but instead of returning the result set, it returns just the cardinality of the result.
The SINTERCARD command was introduced in Redis 7.0.0.
How 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().
Redis SINTERSTORE Command Explained
In Redis, the SINTERSTORE command is the same as the SINTER command, except that it stores the result in the specified key, instead of returning it.
It stores the members of the set resulting from the intersection of all the given sets.
If the destination key already exists, it’s overwritten. If it doesn’t exist, it’s created and the resulting members are added to it.
Continue readingRedis SINTER Command Explained
In Redis, the SINTER command returns the members of the set resulting from the intersection of all the given sets.
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.