我需要用一个查询插入多行(行数不是常量),所以我需要像这样执行查询:

INSERT INTO t (a, b) VALUES (1, 2), (3, 4), (5, 6);

我唯一知道的办法就是

args = [(1,2), (3,4), (5,6)]
args_str = ','.join(cursor.mogrify("%s", (x, )) for x in args)
cursor.execute("INSERT INTO t (a, b) VALUES "+args_str)

但我想要更简单的方法。


当前回答

从@ant32

def myInsertManyTuples(connection, table, tuple_of_tuples):
    cursor = connection.cursor()
    try:
        insert_len = len(tuple_of_tuples[0])
        insert_template = "("
        for i in range(insert_len):
            insert_template += "%s,"
        insert_template = insert_template[:-1] + ")"

        args_str = ",".join(
            cursor.mogrify(insert_template, x).decode("utf-8")
            for x in tuple_of_tuples
        )
        cursor.execute("INSERT INTO " + table + " VALUES " + args_str)
        connection.commit()

    except psycopg2.Error as e:
        print(f"psycopg2.Error in myInsertMany = {e}")
        connection.rollback()

其他回答

使用aiopg -下面的代码段工作得非常好

    # items = [10, 11, 12, 13]
    # group = 1
    tup = [(gid, pid) for pid in items]
    args_str = ",".join([str(s) for s in tup])
    # insert into group values (1, 10), (1, 11), (1, 12), (1, 13)
    yield from cur.execute("INSERT INTO group VALUES " + args_str)

所有这些技术在Postgres术语中都被称为“扩展插入”,截至2016年11月24日,它仍然比psychopg2的executemany()和这个线程中列出的所有其他方法快得多(在得到这个答案之前我尝试过)。

下面是一些不使用cur.mogrify的代码,很好,很简单:

valueSQL = [ '%s', '%s', '%s', ... ] # as many as you have columns.
sqlrows = []
rowsPerInsert = 3 # more means faster, but with diminishing returns..
for row in getSomeData:
        # row == [1, 'a', 'yolo', ... ]
        sqlrows += row
        if ( len(sqlrows)/len(valueSQL) ) % rowsPerInsert == 0:
                # sqlrows == [ 1, 'a', 'yolo', 2, 'b', 'swag', 3, 'c', 'selfie' ]
                insertSQL = 'INSERT INTO "twitter" VALUES ' + ','.join(['(' + ','.join(valueSQL) + ')']*rowsPerInsert)
                cur.execute(insertSQL, sqlrows)
                con.commit()
                sqlrows = []
insertSQL = 'INSERT INTO "twitter" VALUES ' + ','.join(['(' + ','.join(valueSQL) + ')']*len(sqlrows))
cur.execute(insertSQL, sqlrows)
con.commit()

但需要注意的是,如果可以使用copy_from(),则应该使用copy_from;)

我使用的解决方案可以在1毫秒内插入8000条记录

curtime = datetime.datetime.now()
postData = dict()
postData["title"] = "This is Title Text"
postData["body"] = "This a Body Text it Can be Long Text"
postData['created_at'] = curtime.isoformat()
postData['updated_at'] = curtime.isoformat()
data = []
for x in range(8000):
    data.append(((postData)))
vals = []
for d in postData:
    vals.append(tuple(d.values())) #Here we extract the Values from the Dict
flds = ",".join(map(str, postData[0]))
tableFlds =  ",".join(map(str, vals))
sqlStr = f"INSERT INTO posts ({flds}) VALUES {tableFlds}"
db.execute(sqlStr)
connection.commit()
rowsAffected = db.rowcount
print(f'{rowsAffected} Rows Affected')

来自Psycopg2教程页面Postgresql.org的一个片段(见底部):

我想向您展示的最后一项是如何使用字典插入多行。如果你有以下情况:

namedict = ({"first_name":"Joshua", "last_name":"Drake"},
            {"first_name":"Steven", "last_name":"Foo"},
            {"first_name":"David", "last_name":"Bar"})

你可以很容易地将这三行都插入到字典中:

cur = conn.cursor()
cur.executemany("""INSERT INTO bar(first_name,last_name) VALUES (%(first_name)s, %(last_name)s)""", namedict)

它没有节省多少代码,但它确实看起来更好。

Psycopg 2.7新增execute_values方法:

data = [(1,'x'), (2,'y')]
insert_query = 'insert into t (a, b) values %s'
psycopg2.extras.execute_values (
    cursor, insert_query, data, template=None, page_size=100
)

在Psycopg 2.6中,python的方法是:

data = [(1,'x'), (2,'y')]
records_list_template = ','.join(['%s'] * len(data))
insert_query = 'insert into t (a, b) values {}'.format(records_list_template)
cursor.execute(insert_query, data)

解释:如果要插入的数据像in一样以元组列表的形式给出

data = [(1,'x'), (2,'y')]

那么它已经是精确要求的格式

插入子句的值语法需要一个记录列表,如 插入t (a, b)值(1,'x'),(2, 'y') Psycopg使Python元组适应Postgresql记录。

惟一必要的工作是提供一个由psycopg填写的记录列表模板

# We use the data list to be sure of the template length
records_list_template = ','.join(['%s'] * len(data))

并将其放在插入查询中

insert_query = 'insert into t (a, b) values {}'.format(records_list_template)

打印insert_query输出

insert into t (a, b) values %s,%s

现在是常见的Psycopg参数替换

cursor.execute(insert_query, data)

或者只是测试将发送到服务器的内容

print (cursor.mogrify(insert_query, data).decode('utf8'))

输出:

insert into t (a, b) values (1, 'x'),(2, 'y')