In PostgreSQL, we can use the lower() function to convert uppercase characters to their lowercase equivalent, according to the rules of the database’s locale.
Author: Ian
Get the First Day of the Month in PostgreSQL
We can use the following method in PostgreSQL to return the first day of a given month.
This could be the first day of the current month, or the first day of the month based on a date that we specify.
Getting the first day of the month allows us to perform further calculations on the resulting date, like adding a certain number of days to the start of the month, etc.
Continue reading2 Ways to Return Rows that Contain Only Non-Alphanumeric Characters in MySQL
Below are two options for finding those rows that only contain non-alphanumeric characters in MySQL.
Non-alphanumeric characters include punctuation characters like !@#&()–[{}]:;',?/* and symbols like `~$^+=<>“, as well as whitespace characters like the space or tab characters.
Add Hours to a Time Value in PostgreSQL
In PostgreSQL, we can use the + operator to add one or more hours to a time value.
By “time” value, this could be an actual time value, a timestamp, or an interval. We can also add hours to a date value or a date and time combination.
Fix Error: “SELECTs to the left and right of UNION do not have the same number of result columns” in SQLite
If you’re getting “Error: in prepare, SELECTs to the left and right of UNION do not have the same number of result columns…” in when trying to use the UNION operator in SQLite, it’s because one of the SELECT statements is returning more columns than the other.
Calculate the Number of Seconds Since a Particular Date/Time in SQLite
If you need to calculate the number of seconds that have passed since a given date and time, you can use the UNIXEPOCH() function.
Note that this function was introduced in SQLite 3.38.0, so it will only work if you’re using SQLite 3.38.0 or later.
Continue readingINITCAP() – Convert to Initial Caps in PostgreSQL
In PostgreSQL, we can use the initcap() function to format a string of text to use initial capitals. That is, it converts the first letter of each word to upper case and the rest to lower case.
2 Ways to Show All Databases in PostgreSQL (psql)
Here are a couple of ways to show a list of databases when using psql with PostgreSQL.
The first option can be used when we’re already connected to PostgreSQL. The second option can be used when we don’t currently have a connection to Postgres.
Continue readingAdd Days to a Date in SQLite
In SQLite, we can use the DATE() function to add a given number of days to a date.
If we’re dealing with datetime values, we can use the DATETIME() function.
nullvalue: Show NULL Values in SQLite
When using the SQLite command line interface (CLI), by default, whenever a query returns a null value, the output is the empty string ('').
We can change this by using the -nullvalue command line option when launching SQLite.
We can also use the .nullvalue dot command if we’re already in the SQLite CLI.