swift 3 http request for json file and inserting into fmdb - swift3

Question

I'm having trouble inserting data from the JSON file from my server.
I'm getting the error of
Failed to insert initial data into the database.
Error Domain=FMDatabase Code=1 "near "s": syntax error" UserInfo={NSLocalizedDescription=near "s": syntax error} near "s": syntax error
However, 9 of the data entries are inserted into the database before the error occurs and the app doesn't crash too. I'm wondering if it's a problem with the json file on the server or it's the code that I have. Any suggestions would be much appreciated. I only started 2-3 months ago so perfectionists cut me some slack
func insertMovieData() {
if openDatabase() {
let url = URL(string: "http://blahblahblah")
let task = URLSession.shared.dataTask(with: url!) { data, response, error in
guard error == nil else {
print(error!)
return
}
guard let data = data else {
print("Data is empty")
return
}
let json = try! JSONSerialization.jsonObject(with: data, options: [])
print(json)
var query = ""
let jsonObj = JSON(json)
if jsonObj != JSON.null {
for (_, jsonObj) in jsonObj {
let movieTitle = jsonObj["subject"]
let movieCoverURL = jsonObj["message"]
print(movieTitle)
query += "insert into movies values (null, '\(movieTitle)', '\(movieCoverURL)');"
}
}
if !self.database.executeStatements(query) {
print("Failed to insert initial data into the database.")
print(self.database.lastError(), self.database.lastErrorMessage())
}
else {
print(movies)
}
self.database.close()
}
task.resume()
}
}