From MariaDB 10.3, NVL() can be used as an alias for the IFNULL() function. Therefore, both functions enable us to replace NULL values with another value.
MySQL IF() Function Explained
MySQL has an IF() function that provides a convenient way to perform a simple “IF/ELSE” operation.
It works similar to a basic IF/ELSE statement, in that it allows us to check for a condition, and return a different result depending on whether it’s true or not.
More specifically, if the first argument to the IF() function is true, the second argument is returned. If it’s not true, the third argument is returned.
Return the First Monday of Each Month in SQLite
We can use SQLite’s DATE() function to return the first Monday of each month for a given year, based on the date we provide.
But it’s not limited to Monday. We can also get the first Tuesday, Wednesday, Thursday, Friday, etc of each month.
Continue readingGet the Last Day of the Month in PostgreSQL
We can use the following technique in PostgreSQL to return the last day of a given month.
This could be the last day of the current month, or the last day of the month based on a date that we specify.
Continue readingHow COALESCE() Works in MariaDB
In MariaDB, the COALESCE() operator returns the first non-NULL value in the list, or NULL if there are no non-NULL values.
MySQL NULLIF() Explained
In MySQL, NULLIF() is a flow control function that returns NULL if both of its arguments are equivalent. Otherwise it returns the first argument.
Return Non-Numeric Values from a PostgreSQL Database Column
The following PostgreSQL examples return only those rows that don’t have a numeric value in a given column.
Continue reading7 Ways to Find Duplicate Rows in PostgreSQL while Ignoring the Primary Key
Here are seven ways to return duplicate rows in PostgreSQL when those rows have a primary key or other unique identifier column.
This means that the duplicate rows share exactly the same values across all columns with the exception of their primary key/unique ID column.
Continue readingHow to Get the Number of Days in a Month in MySQL
Check out the following technique in MySQL if you need to find out how many days are in a month based on a given date.
Continue readingConvert a Unix Timestamp to a Date Value in Oracle
In Oracle Database, we can use the following technique to return a date from a Unix timestamp value.
The Unix timestamp (also known as Unix Epoch time, Unix time, or POSIX time) is the number of seconds that have elapsed since 00:00:00 Thursday, 1 January 1970, Coordinated Universal Time (UTC).
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