In Redis, the ZDIFFSTORE command computes the difference between the first and all successive input sorted sets and stores the result in the specified key.
ZDIFFSTORE works in the same way as the ZDIFF command, except that it stores the result instead of returning it (ZDIFF returns the result instead of storing it in a new key).
In Redis, the ZDIFF command returns the difference between the first and all successive input sorted sets.
In Redis, the ZCOUNT command returns the number of elements in a sorted set with a score between two given values.
In Redis, the ZREVRANK command returns the rank of the specified element of a sorted set ordered in descending order (from high to low).
If we want the set to be in ascending order, we can use the ZRANK command.
In Redis, the ZRANK command returns the rank of the specified element of a sorted set.
The scores are ordered from low to high. If we want them in the opposite order, we can use the ZREVRANK command.
In Redis, the ZRANDMEMBER command enables us to get one or more random elements from a sorted set.
We can specify whether or not to return only distinct elements or to allow duplicates. We can also specify whether or not to include the scores of each element in the result.
Continue readingIn SQL Server we can query the sys.parameters system catalog view to return all parameters that belong to user-defined objects.
For system objects, we can query the sys.system_parameters view. We can alternatively query the sys.all_parameters system catalog view to return all parameters that belong to either user-defined or system objects.
Starting with Redis 6.2.0, the ZRANGE command added the REV, BYSCORE, BYLEX and LIMIT options. The addition of the first three options means that the ZRANGE command can now do what the ZREVRANGE, ZRANGEBYSCORE, ZREVRANGEBYSCORE, ZRANGEBYLEX and ZREVRANGEBYLEX commands can do.
As a result, those commands are now deprecated (as of Redis 6.2.0).
Therefore, we should no longer use the ZRANGEBYSCORE command when we need to return a sorted set by score. Instead, we should use the ZRANGE command with the BYSCORE argument.
In SQL Server we can create synonyms, which allow us to provide an alternative name for a database object. Once created, we can reference the synonym instead of the object itself.
Continue readingIf you’re getting an error that reads something like “ERROR 1050 (42S01): Table ‘customers’ already exists” when trying to create a table in MySQL, it’s probably because there’s already a table in the database with the same name.
To fix this issue, either change the name of the table you’re trying to create, or check the existing table to see if it’s the one you actually need.
Continue reading