Can't retrieve output parameter with Go MySQL - mysql

Question

I have a stored procedure which inserts an entity and returns its new UUID, and while I can generate the code to create the right query, it errors out when using go-sql-driver/mysql. So the following code...
func test_insert() *sql.Rows {
db := openDbConnection()
defer db.Close()
results, err := db.Query("call saveargument(null, 'Test Argument', 'Test Argument', '1', null, null, null, 1, 'test_user', #newargumentid);\nselect #newargumentid;")
toolkit.HandleError(err)
return results
}
func openDbConnection() *sql.DB {
var db, err = sql.Open("mysql", getConnectionString(entities.GetConfig()))
toolkit.HandleError(err)
return db
}
... produces the following error:
You have an error in your SQL syntax; check the manual that
corresponds to your MySQL server version for the right syntax to use
near 'select #newargumentid' at line 2
I'm not sure why such a basic piece of SQL could be so problematic. Any insights anyone?

Answer 1

You can't run more than one statement in a single db.Query() call. This is true of most query interfaces in all programming languages.
Call your stored procedure in one call to db.Query(), then query select #newargumentid in a second call to db.Query().

Answer 2

I just tested #Bill's answer and I can confirm it does not work as at Go1.14. My workaround was to rewrite my stored procedure to "return" values by doing a select at the end:
CREATE PROCEDURE foo()
BEGIN
# do stuff...
SELECT 'bar';
END;
And then in Go just read it like any other query:
res, _ := db.Query("CALL foo()")
res.Next()
var bar string
res.Scan(&bar)
println(bar)
Note this method also works for multiple columns and multiple rows.