As the title says, I want to check the syntax of a query just before executing it in Python.
For example, a function named check_syntax:
correct_sql = "select * from table;"
wrong_sql = "selecccct * from table;"
check_syntax(correct_sql) # return True
check_syntax(wrong_sql) # return False
I wonder, is there any library in Python that can help? I have looked into sqlparse, but it doesn't help.
This might be un-ideal but you could do:
def check_syntax(request: str) -> bool:
try:
cursor.execute(request)
return True
except:
return False
The problem is that you would not "only check" the syntax. What you could is doing the same but parsing the error message e (except Exception as e) and only returning False if the error code is 102: IncorrectSyntax.
Here is something that could help to parse the exception messages of pyodbc, but depending on what library you use, you'd have to change the class.
pyparsing includes a SELECT statement parser in its examples directory. You could use it like this:
from pyparsing import Optional, ParseException
from select_parser import select_stmt
def check_syntax(s):
try:
(select_stmt + Optional(';')).parseString(s, parseAll=True)
except ParseException as pe:
print(pe.explain())
return False
else:
return True
correct_sql = "select * from table;"
wrong_sql = "selecccct * from table;"
print(check_syntax(correct_sql)) # return True
print(check_syntax(wrong_sql)) # return False
