Below are two methods for returning rows that contain only non-alphanumeric characters in MariaDB.
Non-alphanumeric characters include punctuation characters like !@#&()–[{}]:;',?/* and symbols like `~$^+=<>“, as well as whitespace characters like the space or tab characters.
In SQLite, we can use the DATE() function to subtract one or more days from a date.
For datetime values, we can use the DATETIME() function.
Here’s a nifty trick we can use in MariaDB to return the number of days in a month based on a given date.
If you encounter an error that reads “INSERT has more expressions than target columns” when trying to insert data in Postgres, it’s because you’re trying to insert data into more columns than the table actually contains.
In PostgreSQL, we can use the - operator to subtract one or more minutes from a time value.
By “time” value, this could be an actual time value, a timestamp, or an interval. We can also subtract minutes from a date value or a date and time combination.
If you’re getting error message “Msg 206” that reads “Operand type clash: date is incompatible with int” in SQL Server while trying to add to (or subtract from) a date, it’s probably because you’re trying to perform arithmetic between an integer and a date value.
To fix this issue, either change the date value to a datetime value or use the DATEADD() function.
If you have a column in a SQL Server database table that contains character data, but some rows also contain numbers within that data, you can use the following technique to return just those rows that don’t contain numbers.
Numbers can be represented by words and other symbols, but for the purpose of this article, “number” means “numerical digit”. So we’re finding values that don’t contain any numerical digits.
In SQLite, we can use the DATE() function to add one or more months to a date.
When we’re dealing with datetime values, we can use the DATETIME() function.
Below are six examples that delete duplicate rows from a table in SQLite when those rows have a primary key or unique identifier column.
In these instances, the primary key must be ignored when comparing duplicates (due to the fact that primary keys prevent duplicate rows by definition).