[Sqlalchemy-tickets] Issue #4222: Query yields different result via SQLA than via mysql command line client (zzzeek/sqlalchemy)

[dwt <iss...@bi...>]

New issue 4222: Query yields different result via SQLA than via mysql command line client
https://bitbucket.org/zzzeek/sqlalchemy/issues/4222/query-yields-different-result-via-sqla

dwt:

Hi there,

I have to admit I'm really not sure where this bug is - but at least I could simmer it down to this reproduction that might be helpful to fix it.

First some context: I recently wrote a migration that had a query like this:

```sql
select seq, replace(uuid(), "-", "") from seq_0_to_9
```

which works beautifully from the mysql (mariadb actually) command line client, in that it returns a sequence of UUIDs that are all different.

However, when executed through sqlalchemy, this query returns the same UUID for each result line. 

Here's my reduction:

```python
#!/usr/bin/env python

"""
Versions:
mysql  Ver 15.1 Distrib 10.2.13-MariaDB, for osx10.13 (x86_64) using readline 5.1
PyMySQL==0.8.0
SQLAlchemy==1.2.5
"""

import sqlalchemy as sa
from sqlalchemy import sql
from pprint import pprint

engine = sa.create_engine('mysql+pymysql://test:test@localhost/test?charset=utf8mb4', echo=True)

pprint(engine.execute('select seq, uuid() from seq_0_to_9').fetchall())
pprint(engine.execute('select seq, replace(uuid(), "-", "") from seq_0_to_9').fetchall())

"""
The two queries produce different output, in that the second query 
returns one and the same UUID for each row, while the first returns 
a different UUID for each row.

To the best of my understanding the two queries should return a 
different UUID for each row - and that is also the behaviour I get 
when I do this from the mysql command line client.
"""
```