In MariaDB, you can use the IF NOT EXISTS clause of the CREATE TABLE statement to check whether or not a table of the same name already exists in the database before creating it.
The table will only be created if there isn’t already one with the same name.
Continue readingIn MariaDB, we can query the information_schema.tables table to check the size of a database.
This table returns information about the tables and views in each database on the server. We can group the results and return the aggregate amounts for each database.
Continue readingMost of the major DBMSs provide us with a way to find a string within a string using SQL. By this, I mean use a SQL query to find the position of a substring within a string.
There are several SQL functions that allow us to do this, including INSTR(), LOCATE(), POSITION(), and CHARINDEX(). The function you use will depend on your DBMS, and possibly whether or not you need to specify a starting position.
Most major RDBMSs provide ways for us to format numbers using SQL. Some provide only basic formatting capabilities, while others are more advanced.
Below are examples of formatting a number in some of the more popular RDBMSs.
Continue readingMariaDB includes a RAND() function that returns a random number. More precisely, it returns a DOUBLE precision floating point value v in the range 0 <= v < 1.0.
This is great, but what if you want to generate an integer within a larger range – and a range that you specify?
Fortunately, there’s an easy technique for doing this.
Continue readingHere are some options for subtracting one or more microseconds from a datetime expression in MariaDB.
Continue readingBelow is a quick example of formatting a number as a percentage in MariaDB.
Continue readingBelow are examples of adding a leading zero to a number in SQL, using various DBMSs.
Continue readingMariaDB 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 readingMariaDB has a GROUP_CONCAT() function that enables us to return columns from a query as a delimited list.