Below are examples of using SQL to return the last day of the month across various DBMSs.
This could be the last day of the current month, or the last day of a month based on a given date.
Continue readingAuthor: Ian
Redis MSETNX Command Explained
In Redis, the MSETNX command allows us to set multiple keys at once, but only if none of them exist.
This allows us to set multiple keys representing different fields of a single logical object in a way that ensures that either all the fields are set, or none are set.
Continue readingRedis MGET Command Explained
In Redis, the MGET command allows us to get the values of multiple keys at once. The values are returned in an array reply.
If a specified key doesn’t exist, MGET returns nil for that key.
Redis MSET Command Explained
In Redis, the MSET command allows us to set multiple keys at once. It replaces any existing values, just as SET does.
SQL Server CASE Statement
The SQL Server CASE statement evaluates a list of conditions and returns one of multiple possible result expressions.
Although it’s commonly known as the “CASE statement”, the SQL Server documentation lists it as an expression. Plus it’s referred to as the “CASE expression” in the SQL standard. Some other DBMSs distinguish between the CASE statement and the CASE expression. Either way, here’s a quick rundown on how the “CASE statement” (or CASE expression) works in SQL Server.
Redis SET Command Explained
In Redis, the SET command sets a key to hold a given string value.
If the key already holds a value, it is overwritten with the new value. Also, any previous time to live associated with the key is discarded (assuming a successful SET operation).
Redis GET Command Explained
In Redis, the GET command returns the value of a given key. If the key doesn’t exist, it returns nil.
An error is returned if the value stored at key is not a string.
Redis LASTSAVE Command Explained
When using Redis, we can use the LASTSAVE command to get the Unix time of the last DB save.
More specifically, LASTSAVE returns the Unix time of the last DB save executed with success.
Install Redis on a Mac with Homebrew
Below are the steps that I used to install Redis on my M1 Mac. The M1 Mac (and M2) uses the ARM64 architecture, but this is not a problem, as Redis versions 4.0 and above support the ARM architecture.
Continue readingHow to Convert to Lowercase in SQLite
In SQLite we can use the lower() function to convert uppercase characters to lowercase.