Database Management Systems
If you’re getting error “Msg 8115, Level 16 Arithmetic overflow error converting IDENTITY to data type…” error in SQL Server, it’s probably because you’re trying to insert data into a table when its IDENTITY column has reached its data type’s limit.
An IDENTITY column automatically increments the value that’s inserted with each new row. If the value being inserted is out of the range of the column’s data type, then the above error will occur.
GUIs like SSMS or Azure Data Studio make it easy to see a column’s data type. Usually it’s a simple matter of navigating to the column in the object explorer and you can see the data type right next to the column.
But if you’re using T-SQL, you’ll need to run a query.
Continue readingThere are several ways to format a number as a percentage in SQL, depending on the DBMS being used.
Here are examples of adding a percent sign to a number in some of the most popular DBMSs.
Continue readingIf you’re formatting a number in PostgreSQL, and you want to change the locale so that the correct group and decimal separators are used, here’s how you can do that.
Continue readingIn MariaDB, the COUNT() aggregate function returns a count of the number of non-NULL values of an expression in the rows retrieved by a SELECT statement.
The very useful DROP TABLE IF EXISTS syntax was finally introduced in Oracle Database – Oracle Database 23c to be precise. This syntax allows us to run a DROP TABLE statement without getting an error if the table doesn’t exist.
Earlier versions of Oracle don’t support the IF EXISTS clause. Therefore, if we want to avoid any nasty errors resulting from trying to drop a non-existent table, we need to do a bit of extra work.
Below are three options for dropping a table if it exists in Oracle.
Continue readingIn MariaDB, the AVG() function returns the average value of the given expression.
The DISTINCT option can be used to return the average of the distinct values (i.e. remove duplicates before calculating the average).
NULL values are ignored.
Here are two options we can use to add an option to our sql_mode without wiping all existing options.
In MariaDB, the SUM() aggregate function returns the sum of a given expression.
It can also be used to return the sum of all distinct (unique) values in an expression.
Continue readingIf you use SQLcl to query Oracle Database, you might be aware of the SET SQLFORMAT json option, that makes query results come back as JSON documents.
But there’s also a json-formatted option, which returns the results in a more human readable format.