使用 Python 将列表值传递给 MySQL 查询

Question

I want to pass list values along with other parameter values. following is my scenario. I want to pass multiple values for column "Code" and want to pass single value to "Continent" column.

param = [('AFG', 'IND'),'Asia']
query = "select * from country where Code in (%s) AND Continent = %s"
cursor.execute(query,param)

while executing in Python, I am getting following error.

Failed to execute Query: Failed processing format-parameters; Python 'tuple' cannot be converted to a MySQL type

Answer 1

The trick here is the WHERE IN clause, which isn't really amenable to being parameterized. One option generates an IN clause with the exact number of placeholders in your list:

codes = ('AFG', 'IND')
continent = 'Asia'
params = codes + (continent,)
where_in = ','.join(['%s'] * len(codes))
sql = "SELECT * FROM country WHERE Code IN (%s) AND Continent = %s" % (where_in, '%s')
cursor.execute(sql, params)

To see what the above script actually did, lets look at the various parts:

print(where_in)
print(sql)

%s,%s
SELECT * FROM country WHERE Code IN (%s,%s) AND Continent = %s

The trick here is that we actually use a %s placeholder twice , once for the Python string, and a second time for the SQL query string. Also, we bind a single level tuple containing all bound values:

('AFG', 'IND', 'ASIA')

Answer 2

first you split the list and then you split the tuple.

param = [('AFG', 'IND'),'Asia']
p1,p2=param[0]
query = "select * from country where Code in ('%s','%s') AND Continent = %s" % (p1,p2,param[1])
cursor.execute(query)