Here are three examples of using SQL to find and select the row with the minimum value in a given column.
The examples work in most major RDBMSs, including MySQL, MariaDB, PostgreSQL, SQLite, Oracle, and SQL Server.
Continue readingCategory: Oracle
Oracle INTERSECT Operator Explained
In Oracle Database, the INTERSECT operator is used to create a compound query that returns the intersection of the results of the left and right SELECT statements. In other words, it combines two queries, but returns only those rows that are returned in both queries.
6 Ways to Select Duplicate Rows in Oracle
The following examples return duplicate rows from an Oracle Database table.
Continue readingOracle MINUS Operator Explained
In Oracle Database, the MINUS operator is used to return only unique rows returned by the first query but not by the second.
4 Ways to Find Rows that Contain Uppercase Letters in Oracle
Here are four options for returning rows that contain uppercase characters in Oracle Database.
Continue reading2 Ways to Return Rows that Contain Only Non-Alphanumeric Characters in Oracle
Below are two methods for returning rows that only contain non-alphanumeric characters in Oracle Database.
Alphanumeric characters are alphabetic characters and numeric characters.
Continue readingOracle UNION Operator Explained
In Oracle Database, the UNION operator allows us to combine the results from two queries into a single result set.
5 Ways to Select Rows with the Maximum Value for their Group in SQL
Here are five options for using SQL to return only those rows that have the maximum value within their group.
These examples work in most major RDBMSs, including MySQL, MariaDB, Oracle, PostgreSQL, SQLite, and SQL Server.
Continue reading3 Ways to Create a Table if it Doesn’t Already Exist in Oracle
The very useful CREATE TABLE IF NOT EXISTS syntax was finally introduced in Oracle Database – Oracle Database 23c to be precise. This syntax allows us to run a CREATE TABLE statement without getting an error if the table already exists.
Earlier versions of Oracle don’t support the IF NOT EXISTS clause, and so if we want to avoid any nasty errors resulting from trying to create a table that already exists, we need to do a bit of extra work.
How to Format Numbers as Roman Numerals in Oracle
When using the TO_CHAR() function in Oracle Database, you can use the RN format element to return the number as roman numerals. Using lowercase (rn) returns the roman numerals in lowercase.