my table looks something like this
id effect1(int) effect2(int) effect3(int)
1 0 1 5
2 1 0 0
i have a function, which return 1to3 int value representing effect1,effect2,effect3 and "id"
i am trying to increment value of each effect by 1 when my function's returning "id" matches the "id" from my dataset otherwise creates new row and increase value of effect
for example
if my function returns (1,3) my table will become
id effect1(int) effect2(int) effect3(int)
1 0 1 6
2 1 0 0
if my function returns (3,3) my table will become
id effect1(int) effect2(int) effect3(int)
1 0 1 6
2 1 0 0
3 0 0 1
i have tried the following code using python, but failed. can someone please help me out here
i = (1,3) # the returning value from my function
if i[1] == 1:
sql = "update test set effect1=effect1+1 WHERE id= ({})".format((str(i[0])))
db.execute_query(myDb, sql)
elif i[1] == 2:
sql = "update test set effect2=effect2+1 WHERE id= ({})".format((str(i[0])))
val = (i[0],)
db.execute_query(myDb, sql )
elif i[1] == 3:
sql = "update test set effect3=effect3+1 WHERE id= ({})".format((str(i[0])))
val = (i[0],)
db.execute_query(myDb, sql )
def execute_query(connection, query):
cursor = connection.cursor()
try:
cursor.execute(query)
connection.commit()
print("Query successful")
except Exception as err:
print(f"Error: '{err}'")
In your implementation, you did not check if the id
already exists or not.
I updated your code with an SQL statement that performs insertion/update as you mentioned-
id
exists then only the specific effect needs to be increasedid
does not exist then a new row with that id
needs to be added/inserted into the test
table)I also replaced the variable i
(a list of two elements), with two variables named id
and effect_no
to improve the readability of the code. The if
else
statements are also not needed as the effect_no
can be used/incorporated into the sql statement itself.
Following is the updated code:
id, effect_no = (1,3) # the returning value from your function
sql = f"""INSERT INTO test (id, effect1, effect2, effect3)
VALUES ({id}, 0, 0, 0)
ON DUPLICATE KEY UPDATE effect{effect_no} = effect{effect_no} + 1"""
db.execute_query(myDb, sql)
def execute_query(connection, query):
cursor = connection.cursor()
try:
cursor.execute(query)
connection.commit()
print("Query successful")
except Exception as err:
print(f"Error: '{err}'")
Also, I found the INSERT ... ON DUPLICATE KEY UPDATE
SQL statement here https://chartio.com/resources/tutorials/how-to-insert-if-row-does-not-exist-upsert-in-mysql/#using-insert--on-duplicate-key-update