In Redis, the ZCOUNT
command returns the number of elements in a sorted set with a score between two given values.
Author: Ian
Redis ZREVRANK Command Explained
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.
Redis ZRANK Command Explained
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.
Redis ZRANDMEMBER Command Explained
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 readingGet All Parameters from a SQL Server Database (T-SQL)
In 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.
Redis ZRANGEBYSCORE Replacement
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.
How to Create a Synonym in SQL Server (T-SQL)
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 readingFix ERROR 1050 (42S01) “Table … already exists” in MySQL
If 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 readingRedis ZRANGE Command Explained
In Redis, the ZRANGE
command returns the specified range of elements in the sorted set stored at the specified key.
It can perform different types of range queries: by index (rank), by the score, or by lexicographical order.
Continue reading3 Ways to Clone a Table in MariaDB using SQL
We have several options when it comes to using SQL to clone a table in MariaDB. And we have the option to clone the table with data, or without data.
Here are three SQL options for cloning a table in MariaDB.
Continue reading