Here are four options for showing all views within an SQLite database.
Continue readingCategory: DBMS
Database Management Systems
PostgreSQL GROUP_CONCAT() Equivalent
Some RDBMSs like MySQL and MariaDB have a GROUP_CONCAT() function that allows you to return a query column as a delimited list (for example, a comma separated list).
PostgreSQL has a similar function called STRING_AGG(). This function works in pretty much the same way that GROUP_CONCAT() works in MySQL and MariaDB.
SQL LPAD()
In SQL, LPAD()is a commonly used function that pads the left part of a string with a specified character. The function can be used on strings and numbers, although depending on the DBMS, numbers may have to be passed as a string before they can be padded.
DBMSs that have an LPAD() function include MySQL, MariaDB, PostgreSQL, and Oracle.
DBMSs that don’t have an LPAD() function include SQL Server and SQLite (although there are other ways to apply left padding in these DBMSs).
SQL RPAD()
In SQL, RPAD()is used to pad the right part of a string with a specified character. The function can be used on strings and numbers, although depending on the DBMS, numbers may have to be passed as a string before they can be padded.
DBMSs that have an RPAD() function include MySQL, MariaDB, PostgreSQL, and Oracle.
DBMSs that don’t have an RPAD() function include SQL Server and SQLite.
DROP TABLE IF EXISTS in MySQL
In MySQL, we can use the IF EXISTS clause of the DROP TABLE statement to check whether the table exists or not before dropping it.
Fix “Conversion failed when converting the varchar value” When Trying to Concatenate in SQL Server
If you get error Msg 245 that reads “Conversion failed when converting the varchar value…” when trying to perform a concatenation operation in SQL Server, it’s likely that you’re attempting to concatenate a string and a number.
Doing this will result in an error, due to SQL Server trying to add the string and number instead of concatenate them.
To fix this, either convert the number to a string, or use a function like CONCAT() or CONCAT_WS() to perform the concatenation.
Format a Number as Currency in SQL
Some DBMSs have functions that allow us to format numbers as currency just by passing the appropriate format string. This converts the number to a string with the applicable currency symbol, group separator, and decimal point (if relevant).
Other DBMSs don’t make it that easy, and you need to do a bit of work first.
Below are examples of using SQL to format numbers as currency in some of the most popular DBMSs.
Continue readingHow to Change the Recovery Model of a SQL Server Database using T-SQL
SQL Server has three recovery models; simple, full, and bulk logged. Each database uses one of these settings.
Backup and restore operations occur within the context of the recovery model of the database
You can change the recovery model of a database by using the ALTER DATABASE statement along with the SET RECOVERY option.
Select Everything Before or After a Certain Character in MariaDB
In MariaDB, you can use the SUBSTRING_INDEX() function to return everything before or after a certain character (or characters) in a string.
Get the Size of All Databases in PostgreSQL (psql)
When using psql with PostgreSQL, we can use the \list+ command to return information about all databases on the server.
We can also use the short form (\l+) to achieve the same result.