PostgreSQL ANSI,Python SQL, utf-8' codec can't decode byte 0xa0

Question

I am trying to run a sql query in python. In python 2 this used to work but now that I am using python 3 this no longer is working.

I get error UnicodeDecodeError: 'utf-8' codec can't decode byte 0xa0 in position 1: invalid start byte

Update, added in the 3 lines in the middle,also tried using 'windows-1252' here. same error:

conn_str = 'DSN=PostgreSQL30'
conn = pyodbc.connect('DSN=STACK_PROD')


###newly added
    conn.setdecoding(pyodbc.SQL_CHAR, encoding='utf-8')
    conn.setdecoding(pyodbc.SQL_WCHAR, encoding='utf-8')
    conn.setencoding(encoding='utf-8')

sql = "select * from stackoverflow where p_date = " + business_date
print("Query: " + sql)
crsr = conn.execute(sql)

traceback:

Traceback (most recent call last):

  File "<ipython-input-2-b6db3f5e859e>", line 1, in <module>
    runfile('//stack/overflow/create_extract_db_new.py', wdir='//stack/overflow')

  File "C:\Users\stack\AppData\Local\Continuum\anaconda3\anaconda3_32bit\lib\site-packages\spyder_kernels\customize\spydercustomize.py", line 827, in runfile
    execfile(filename, namespace)

  File "C:\Users\stack\AppData\Local\Continuum\anaconda3\anaconda3_32bit\lib\site-packages\spyder_kernels\customize\spydercustomize.py", line 110, in execfile
    exec(compile(f.read(), filename, 'exec'), namespace)

  File "//stack/overflow/create_extract_db_new.py", line 37, in <module>
    crsr = conn.execute(sql)

Also tried:

conn.setdecoding(pyodbc.SQL_CHAR, encoding='windows-1252')
conn.setdecoding(pyodbc.SQL_WCHAR, encoding='windows-1252')
conn.setencoding(encoding='windows-1252')

UnicodeDecodeError: 'utf-8' codec can't decode byte 0xd5 in position 1: invalid continuation byte

Also tried:

    conn.setdecoding(pyodbc.SQL_CHAR, encoding='utf-8')
    conn.setdecoding(pyodbc.SQL_WCHAR, encoding='utf-16')
    conn.setencoding(encoding='utf-8')    

UnicodeDecodeError: 'utf-8' codec can't decode byte 0xd5 in position 1: invalid continuation byte

Also tried:

conn.setdecoding(pyodbc.SQL_CHAR, encoding='utf-8')
conn.setdecoding(pyodbc.SQL_WCHAR, encoding='utf-8')
conn.setencoding(encoding='utf-8')
conn.setdecoding(pyodbc.SQL_WMETADATA, encoding='windows-1252')

UnicodeDecodeError: 'utf-8' codec can't decode byte 0xd5 in position 1: invalid continuation byte

Also tried:

conn.setdecoding(pyodbc.SQL_CHAR, encoding='windows-1252')
conn.setdecoding(pyodbc.SQL_WCHAR, encoding='windows-1252')
conn.setencoding(encoding='windows-1252')
conn.setdecoding(pyodbc.SQL_WMETADATA, encoding='windows-1252')

UnicodeDecodeError: 'utf-8' codec can't decode byte 0xd5 in position 1: invalid continuation byte

Dump Dsn Results, omitting my username, uid, password and server.:

[my_dsn]
Driver=C:\Program Files (x86)\psqlODBC\0903\bin\psqlodbc30a.dll
CommLog=0
Debug=0
Fetch=100
Optimizer=0
Ksqo=1
UniqueIndex=1
UseDeclareFetch=0
UnknownSizes=0
TextAsLongVarchar=1
UnknownsAsLongVarchar=0
BoolsAsChar=1
Parse=0
CancelAsFreeStmt=0
MaxVarcharSize=255
MaxLongVarcharSize=8190
ExtraSysTablePrefixes=dd_;
Description=my_dsn
Database=db_name
Port=9996
ReadOnly=0
ShowOidColumn=0
FakeOidIndex=0
RowVersioning=0
ShowSystemTables=0
Protocol=7.4
ConnSettings=
DisallowPremature=0
UpdatableCursors=1
LFConversion=1
TrueIsMinus1=0
BI=0
AB=0
ByteaAsLongVarBinary=0
UseServerSidePrepare=1
LowerCaseIdentifier=0
GssAuthUseGSS=0
SSLmode=disable
KeepaliveTime=-1
KeepaliveInterval=-1
PreferLibpq=-1
XaOpt=1

Error msg:

UnicodeDecodeError: 'utf-8' codec can't decode byte 0xe4 in position 3: unexpected end of data

can anyone help me ?

Answer 1

When using PostgreSQL's Unicode driver you need to call setencoding and setdecoding as explained here.

# Python 3.x
cnxn.setdecoding(pyodbc.SQL_CHAR, encoding='utf-8')
cnxn.setdecoding(pyodbc.SQL_WCHAR, encoding='utf-8')
cnxn.setencoding(encoding='utf-8')

If you are using PostgreSQL's "ANSI" driver then you may still need to call those methods to ensure that the correct single-byte character set (a.k.a. "code page", e.g., windows-1252) is used for SQL_CHAR.