python - WHERE NOT EXISTS SQL statement in sqlite3 -

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• “insert if not exists” statement in sqlite 4 answers

my code this:

import sqlite3 def connect():     conn = sqlite3.connect("books.db")     cur = conn.cursor()     cur.execute("create table if not exists book (id integer primary key, title text, author text, year integer)")     conn.commit()     conn.close() def insert(title, author, year):     conn = sqlite3.connect("books.db")     cur = conn.cursor()     cur.execute("insert book values (null, ?, ?, ?)", (title, author, year))     conn.commit()     conn.close() connect() insert("title", "author", 1950) 

i use not exists sql statement in order avoid duplicate inputs. tried different ways of writing in not exists along cur.execute() keep getting:

sqlite3.operationalerror: near "where": syntax error

to avoid duplicate inserts, use unique index or constraint:

create unique index unq_book_title_author_year on book(title, author, year); 

this better not exists because database enforces uniqueness. note insert attempted , fail, if duplicate insertions attempted.