We can use the - operator to subtract one or more weeks from a date in PostgreSQL.
DBMS
Database Management Systems
How IFNULL() Works in MariaDB
In MariaDB, the IFNULL() function allows 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.
Get 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.
How 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.
7 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.