Here you are shown how to issue queries without using a table.
This is done in different ways across different platforms but all of them will give a single row of information.
causes the response speed of the query to slow down.
Only certain functions can be used without a table and these functions are called static functions.
Static functions can allow a user to obtain the current username, current date, current timestamp and also the version of the database being used.
SELECT CURRENT_USER, CURRENT_DATE
SELECT USER, CURRENT_DATE FROM dual
SELECT SYSTEM_USER, GETDATE()
SELECT ENVIRON('username'), Date()
SELECT USER, CURRENT_DATE, CURRENT_TIMESTAMP, (SELECT banner FROM v$version WHERE ROWNUM = 1), DBMS_RANDOM.RANDOM(), SYS_GUID()FROM dual
SELECT CURRENT_USER, CURRENT_DATE, CURRENT_TIMESTAMP,VERSION(), RAND(), UUID()
SELECT SYSTEM_USER, CAST(CAST(GetDate() AS INT) AS DATETIME),GetDate(), @@VERSION, RAND(), NEWID()
SELECT CURRENT_USER, CURRENT_DATE, CURRENT_TIMESTAMP,VERSION(), RANDOM()
then create a query in that database and then run the function given in the example in SQL view.