trying to insert values into one MySQL table using python.
First inserting values from csvfile; with:
sql = "INSERT INTO mydb.table(time,day,number)values %r" % tuple (values),)
cursor.execute(sql)
then insert into the same table and same row an other value
sql = "INSERT INTO mydb.table(name) values(%s)"
cursor.execute(sql)
with this i get the inserts in two different rows…
But i need to insert it into the same row without using sql = "INSERT INTO mydb.table(time,day,number,name)values %r" % tuple (values),)
Is there a way to insert values into the same row in two 'insert statements'?
INSERT will always add a new row. If you want to change values in this row, you have to specify a unique identifier (key) in the WHERE clause to access this row and use UPDATE or REPLACE instead.
When using REPLACE you need to be careful if your table contains an auto_increment column, since a new value will be generated.
Related
From my list, I am looking to insert row by row, but I need to perform a checking before allowing to insert in the database.
let's imagine that is my list
unique_hrefs = [
https://www.linkedin.com/in/123456,
https://www.linkedin.com/in/789013556,
https://www.linkedin.com/in/888888888,
https://www.linkedin.com/in/082b62112,
https://www.linkedin.com/in/5625a1a,
https://www.linkedin.com/in/123456,
https://www.linkedin.com/in/0000000341454,
https://www.linkedin.com/in/55555555,
https://www.linkedin.com/in/55555555,
https://www.linkedin.com/in/66666666,
https://www.linkedin.com/in/666677777
]
I need to check my table for the same string before allowing to inserting and if the string does not exist inserting.
I have my code to inset but struggling to find how to check before inserting it?
query= "INSERT INTO name_links (ulr_name) VALUES (%s)
cursor.executemany(query,[(r,) for r in unique_hrefs])
mydb.commit()
In python script i have insert query but when i want insert multiple columns in the same query it gives error.
but for single query it works perfectly.
Below is my code.
my database AWS S3.
A = [] #
for score_row in score:
A.append(score_row[2])
print("A=",A)
B = [] #
for day_row in score:
B.append(day_row[1])
print("B=",B)
for x,y in zip(A,B):
sql = """INSERT INTO calculated_corr_coeff(date,Day) VALUES (?,?)"""
cursor.executemany(sql, (x,),(y,))
when i replace above query with following sql insert statement it works perfect.
sql = """INSERT INTO calculated_corr_coeff(date,Day) VALUES (?)"""
cursor.executemany(sql, (x,))
Fix your code like this:
sql = """INSERT INTO calculated_corr_coeff(date,Day) VALUES (?,?)"""
cursor.execute(sql, (x,y,)) #<-- here
Because is just a onet insert ( not several inserts )
Explanation
I guess you are mistaked about number of inserts ( rows ) and number of paràmeters ( fields to insert on each row ). When you want to insert several rows, use executemany, just for one row you should to use execute. Second parapeter of execute is the "list" (or sequence ) of values to be inserted in this row.
Alternative
You can try to change syntax and insert all data in one shot using ** syntax:
values = zip(A,B) #instead of "for"
sql = """INSERT INTO calculated_corr_coeff(date,Day) VALUES (?,?)"""
cursor.executemany(sql, **values )
Notice this approach don't use for statement. This mean all data is send to database in one call, this is more efficient.
I need to update columns values in csv to mysql database and the csv values are dynamic for one file it may be 10 columns and for other it may be 5 columns.
my understanding in python we need to use list also this question raised earlier is similar to my requirement but here the values are static so it can be predefined where's in my case being dynamic need to a solution to have %%s under VALUES to be multiplied according to my column values dynamically.
MySQL Dynamic Query Statement in Python
ds_list=['name','id','class','chapter','MTH','YEAR']
vl_list=['xxxxx','978000048','x-grade','Science',mar,2017]
sql = 'INSERT INTO ann1 (%s) VALUES (%%s, %%s, %%s, %%s, %%s, %%s)' % ','.join(ds_list)
cur.execute(sql, vl_list)
conn.commit()
So, if you have two lists, one with headers and the other with values – you can create yourself dynamic INSERT query.
query_placeholders = ', '.join(['%s'] * len(vl_list))
query_columns = ', '.join(ds_list)
insert_query = ''' INSERT INTO table (%s) VALUES (%s) ''' %(query_columns, query_placeholders)
and then execute & commit your query by passing list with values in query.
cursor.execute(insert_query, vl_list)
I am attempting to insert Excel spreadsheets into a Postgres DB using a Python script with psychopg2.
The problem is not all the spreadsheets have the same number of columns, and I need the insert statement to be flexible enough so I don't have to specify them by name.
My approach is to load the columns of the spreadsheet's header row into a tuple, and likewise with the values being inserted. So for example:
sql = ''''INSERT INTO my_table (%s) VALUES (%s);'''
cur.execute(sql, (cols, vals))
where 'cols' and 'vals' are both tuples.
'cols' can have 7, 9, 10, etc. entries, again depending on how many columns the spreadsheet had.
When I attempt to run this, I get:
psycopg2.ProgrammingError: syntax error at or near "'INSERT INTO my_table
(ARRAY['"
LINE 1: 'INSERT INTO my_table...
^
Not sure if the problem is in my calling syntax, or if you simply can't do what I'm trying to do.
There's an apostrophe ' at the beginning of your sql query.
''''INSERT INTO my_table (%s) VALUES (%s);'''
should be
'''INSERT INTO my_table (%s) VALUES (%s);'''
Edit: didn't realize you where trying to query columns dynamically. To do that, you should use text formatting. Asuming cols is a list:
sql = '''INSERT INTO my_table ({}) VALUES (%s)'''.format(','.join(cols))
Then, your execution would be:
cur.execute(sql, (vals,))
I'm looking for a simple upsert (Update/Insert).
I have table in which I am inserting rows for books table but next time when I want to insert row I don't want to insert again data for that table just want to update with required columns if it exits there if not then create new row.
How can I do this in Mysql-python?
cursor.execute("""INSERT INTO books (book_code,book_name,created_at,updated_at) VALUES (%s,%s,%s,%s)""", (book_code,book_name,curr_time,curr_time,))
MySQL has REPLACE statement:
REPLACE works exactly like INSERT, except that if an old row in the
table has the same value as a new row for a PRIMARY KEY or a UNIQUE
index, the old row is deleted before the new row is inserted.
cursor.execute("""
REPLACE INTO books (book_code,book_name,created_at,updated_at)
VALUES (%s,%s,%s,%s)""",
(book_code,book_name,curr_time,curr_time,)
)
UPDATE According to comment of #Yo-han, REPLACE is like DELETE and INSERT, not UPSERT. Here's alternative using INSERT ... ON DUPLICATE KEY UPDATE:
cursor.execute("""
INSERT INTO books (book_code,book_name,created_at,updated_at)
VALUES (%s,%s,%s,%s)
ON DUPLICATE KEY UPDATE book_name=%s, created_at=%s, updated_at=%s
""", (book_code, book_name, curr_time, curr_time, book_name, curr_time, curr_time))