Mariadb - Diffferences between executing a file vs pasting same code into console - console

Question

I’m trying to make the move from SQL Server to Mariadb and I’m running into a lot of little quirks that drive me crazy at times. Chief among them are the apparent differences between executing a script from a file and pasting it into a console window. I was used to using tabs for formatting code in MSSQL, so I’m still trying to get used to the tab behavior in the Mariadb console, but at least that makes sense. The difference between var and #var is odd to me as well. The code below runs fine when execute through Pycharm, but fails when pasted into a console window. I’m running Mariadb (##version: 10.5.18-MariaDB-0+deb11u1) on a Pi Raspberry accessing it through SSH from a Windows 11 box.
All the script is doing is populating a table with random combinations of last names and male/female first names from U.S. census data for testing. Any help with the error would be greatly appreciated. I really want to understand why the difference between pasting and executing the file.
SET #loops := 10;
WHILE #loops > 0 DO
INSERT person(last_name, first_name, iso_country)
VALUES(census.random_name(0), census.random_name(FLOOR(1 + RAND() * (2 - 1 +1))), 'US');
SET #loops := #loops - 1;
END WHILE;
SELECT * FROM person;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'END WHILE' at line 1
I executed the file from the Pycharm IDE where it runs fine, and pasted the same code into the Mariadb console where the error was raised, and the insertions did not occur.

Answer 1

The mariadb command line client has it's own small parser, by default a semicolon is interpreted as end of statement.
With default delimiter ; your statement is splitted after first semicolon into WHILE #loops > 0 DO INSERT person(last_name, first_name, iso_country) VALUES(census.random_name(0), census.random_name(FLOOR(1 + RAND() * (2 - 1 +1))), 'US'); SET #loops := #loops - 1; and END WHILE. When sending both statements to the server, server will return 2 errors, but only last error is displayed.
Instead you should use a different delimiter:
DELIMITER $$
WHILE #loops > 0 DO
INSERT person(last_name, first_name, iso_country)
VALUES(census.random_name(0), census.random_name(FLOOR(1 + RAND() * (2 - 1 +1))), 'US');
SET #loops := #loops - 1;
END WHILE;$$
See also Delimiters