Lots of various ways to count things, what and how (including terrorism, not, etc.) and get various results. But very clearly not something that "doesn't happen anywhere else."
Same with school shootings:
Aarhus University shooting Aarhus, Denmark April 5 1994 3 (including the perpetrator) 35-year-old student Flemming Nielsen shot and killed two people and wounded two others with a sawed-off shotgun before taking his own life.
Dunblane massacre Dunblane, United Kingdom March 13 1996 19 (including the perpetrator and the unborn child) 43-year-old Thomas Hamilton opened fire in a gymnasium, killing sixteen children and one adult and injuring fifteen others before committing suicide. It remains the deadliest attack on children in British history.
ROC de Leijgraaf Veghel, Netherlands December 7 1999 0 A 17-year-old student opened fire at ROC de Leijgraaf school, wounding three students and one teacher. One student was critically injured. It was the first school shooting in the history of the Netherlands.
Erfurt massacre Erfurt, Germany April 26 2002 17 (including the perpetrator) 19-year-old Robert Steinhäuser began shooting through his former school, targeting teachers and faculty members. Twelve teachers and one administrator were killed, along with two students and a police officer; only one other person was injured. The shooter then committed suicide.
Coburg shooting Coburg, Germany July 3 2003 1 (the perpetrator) A 16-year-old student, known only as Florian K., shot and wounded his teacher and an intervening school psychiatrist before taking his own life.
Terra College The Hague, Netherlands January 2004 1 A student shot the school principal, Hans van Wieren, in the head.
Rötz school shooting Rötz, Germany March 7 2005 0 After being ordered to leave the classroom, a 14-year-old student returned with a gun and threatened the life of the 35-year-old class teacher. During a struggle the weapon was fired and taken from the student. Investigators' findings state that the student did not intend to kill the teacher, but himself. No one was injured.
Geschwister Scholl School attack Emsdetten, Germany November 20 2006 1 (the perpetrator) 18-year-old Bastian Bosse, a former student of the school, fired several shots with two sawed-off rifles and a caplock pistol and also threw several homemade smoke bombs before killing himself. The incident ended with no other fatalities, with 37 people being injured, including four students who suffered gunshot wounds, one teacher wounded by being hit in the face with a smoke bomb, sixteen police officers who suffered from smoke inhalation, and the school custodian who was shot in the abdomen inside the school.
Jokela school shooting Tuusula, Finland November 7 2007 9 (including the perpetrator) 18-year-old Pekka-Eric Auvinen opened fire in the school's main hallway, killing six students, school principal Helena Kalmi, and the school nurse before shooting and wounding himself in a suicide attempt; he later died at a hospital. One other person suffered gunshot wounds, and eleven people were injured by shattering glass while escaping from the school building. The day before the incident, Auvinen posted a video on YouTube predicting the massacre at the school.
Kauhajoki school shooting Kauhajoki, Finland September 23 2008 11 (including the perpetrator) 22-year-old student Matti Juhani Saari entered the school via the basement and opened fire in a classroom he attended before setting it on fire with homemade Molotov cocktails and then fleeing the scene. Nine students and one staff member died in the incident. A woman was shot in the head and critically wounded, but survived after having two operations, while ten other students sustained minor injuries such as sprains and cuts from broken glass. Authorities eventually found Saari, who had shot himself but was still alive; he died a short time later. It was assumed that the Jokela case, the previous year (above), inspired Saari to commit the massacre.
Winnenden school shooting Winnenden, Germany March 11 2009 16 (including the perpetrator) 17-year-old Tim Kretschmer, a former student of the school, opened fire in two classrooms and a chemistry laboratory, killing nine and injuring seven others. He then successfully escaped the school, killing two female teachers in the process. Afterwards, he shot and killed the caretaker of a psychiatric facility and then carjacked a motorist, who drove him into another town before escaping unharmed. The shooter opened fire in a car showroom after unsuccessfully trying to steal a car, killing two and injuring two others. He then committed suicide after a brief shootout with police.
OAED Vocational College shooting Athens, Greece April 10 2009 1 (the perpetrator) 19-year-old Dimitris Patmanidis shot and wounded a student and two workers from a nearby technical company before shooting and wounding himself in the head in a suicide attempt. He died later at a hospital.
Kanebogen Elementary School shooting Harstad, Norway April 28 2009 0 A nine-year-old student fired a shotgun in schoolyard; however, nobody was injured in the incident. The shooter was disarmed and subdued by a female teacher, but due to his age, he wasn't tried for the crime, although his father was fined for not keeping the shotgun, a rifle, and ammunition according to Norwegian rules. This was the first Norwegian school shooting.
University of Pécs shooting Pécs, Hungary November 26 2009 1 A 23-year-old student entered the building of the university's biophysics research institute and opened fire in the classroom, killing one man. In earlier reports, two people were reported to be in critical condition and a third in serious condition.
Toulouse school shooting Toulouse, France March 19 2012 5 (including the perpetrator) 23-year-old Mohammed Merah opened fire at a Jewish day school, killing three schoolchildren and a teacher. The incident was the last of three terrorist attacks against French soldiers and Jewish civilians, occurring in an eight-day span. The shooter was later shot and killed by police after a massive three-day manhunt and a 30-hour standoff at his home.
2014 Moscow school shooting Moscow, Russia February 3 2014 2 High school student Sergey Gordeyev, armed with two rifles, forced his way past a security guard, took hostages, and killed his geography teacher. He then killed a police officer and wounded another who arrived at the scene. He later released the hostages and was captured by the police after his father came to the school.
2014 Viljandi school shooting Viljandi, Estonia October 27 2014 1 A 15-year-old boy killed his German language teacher with a gun in Paalalinna school. All students were evacuated in school hall and police arrested the shooter. As of now, it remains unclear as to why the shooting took place.
2015 Joan Fuster school shooting Barcelona, Spain April 20 2015 1 A 13-year-old boy armed with a crossbow and a machete killed a teacher and injured 4. The first ever student to organise a school shooting in Spain had a breakdown when his PE teacher managed to talk with him, then proceeded to sit in a classroom until the police arrived. Under Spanish law, the boy is exempt from legal responsibility because he's under 14.
Tocqueville high school shooting Grasse, France March 16 2017 0 Kylian Barbey, a 17-year-old boy, armed with a rifle, two handguns, a revolver and two grenades opened fire at Alexis de Tocqueville high school. A total of four were injured, three students and the school's principal. Anti-terrorist commandos were sent to the scene and the shooter was arrested. The perpetrator's Facebook and YouTube accounts showed that he was interested in the Columbine Massacre and watched videos on how to make homemade weapons.
Shadrinsk school shooting Shadrinsk, Russia March 21 2018 0 A 13-year-old girl opened fire with a gas pistol at her school in Russia's Kurgan region, injuring seven seventh graders. The victims suffered bruises and scrapes.
Barabinsk college shooting Barabinsk, Russia May 10 2018 1 (the perpetrator) A college student shot another student with a double-barreled shotgun and shot himself.
Kerch Polytechnic College massacre Kerch, Crimea October 17 2018 21 (including the perpetrator) A bomb exploded on the first floor and then Vladislav Roslyakov, an 18-year-old boy, started shooting people in the college's dining room on the second floor. A total of 21 people died and over 50 people were injured.