Even though Oracle Database has a TO_CHAR(number) function that allows us to format numbers, it doesn’t provide a format element for the percentage sign.
Therefore, if we want to format a number as a percentage in Oracle Database, we need to concatenate the percentage sign and the number.
Continue readingIn MySQL, we can format a number as a percentage by concatenating the number with the percent sign.
The CONCAT() function concatenates its arguments. We can pass the number as the first argument, and the percent sign as the second.
Here are two ways to format a number as a percentage in SQLite.
Continue readingWhen querying Oracle Database, you can use the SPOOL command to export your query results to a text file when using SQLcl.
If you’ve ever used the TO_CHAR() function to format a date that uses the month name, you might have noticed that sometimes the month is returned with right padding.
Many RDBMSs have an INSTR() function that enables us to find a substring within a string. Some (such as MySQL and MariaDB) also have a LOCATE() function and a POSITION() function (also supported by PostgreSQL), that do a similar thing.
SQL Server doesn’t have an INSTR() function. Nor does it have a LOCATE() or POSITION() function. But it does have the CHARINDEX() function that does the same thing.
SQL Server also has the PATINDEX() function, which does a similar job to CHARINDEX().
MariaDB has several functions that enable you to extract various date and time parts from date/time values. You can use these to separate each date/time component into its own column if required.
Below are three ways to extract the year, month, and day from a date value in MariaDB.
Continue readingBy default, null values are returned as an empty string in psql. But this can easily be changed.
One reason you might want to change this is to avoid null values being confused with actual empty strings.
You can change this with the \pset null 'value' command.
In SQLite, we can use the PRINTF() function or FORMAT() function to format numbers with leading zeros.
MariaDB has an LPAD() function that allows us to pad the left part of a string or number with our chosen character or series of characters.
We can use this function on numeric values in order to add leading zeros.
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