# Df = (session.sql(sql\_query).to\_pandas()) returns all columns as string

**URL:** <https://www.starburst.io/community/forum/t/df-session-sql-sql-query-to-pandas-returns-all-columns-as-string/1358>\
**Category:** SQL\
**Tags:** python\
**Created:** [December 19, 2025, 3:51pm UTC](https://www.starburst.io/community/forum/t/df-session-sql-sql-query-to-pandas-returns-all-columns-as-string/1358 "2025-12-19T15:51:29Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![gathe](https://www.starburst.io/community/forum/letter_avatar_proxy/v4/letter/g/59ef9b/32.png) [@gathe](https://www.starburst.io/community/forum/u/gathe)\
**Post date:** [December 19, 2025, 3:51pm UTC](https://www.starburst.io/community/forum/t/df-session-sql-sql-query-to-pandas-returns-all-columns-as-string/1358/1 "2025-12-19T15:51:29Z")

</div>

I’m converting pystarburst dataframes into pandas so that my colleagues can interact using familiar techniques.

However, the conversion returns all columns as object (string/varchar) instead of the original data types from the SQL schema.

Here is the python workflow:

````auto

import trino
from pystarburst import Session

# Connection parameters
db_parameters = {
    "host": "",
    "port": "",
    "http_scheme": "",
    "catalog" : "",
    "schema": "",
    "verify": "",
    "auth": trino.auth.BasicAuthentication(
        "usr",
        "pwd"
    )
}

session = Session.builder.configs(db_parameters).create()

sql_query = """
SELECT
    column1, -- varchar
    column2, -- decimal(18,2)
    column3 -- date
FROM schema.table
WHERE column1 LIKE 'A%'
"""

df = (session.sql(sql_query).to_pandas()) # Convert to pandas as colleagues are familiar

df.info(verbose=True) # All the columns return as "object" making it difficult for them to do ETL in the next step

df = normalize(df) # ETL based on pandas library so colleagues can adjust

df.to_parquet("file_path", index=None) # Results saved for analytical use
```

````

---

<div class="post-metadata">

**Author:** ![lester](https://www.starburst.io/community/forum/user_avatar/www.starburst.io/lester/32/138_2.png) [@lester](https://www.starburst.io/community/forum/u/lester)\
**Post date:** [December 19, 2025, 10:50pm UTC](https://www.starburst.io/community/forum/t/df-session-sql-sql-query-to-pandas-returns-all-columns-as-string/1358/2 "2025-12-19T22:50:43Z")

</div>

I’m running the following on Starburst Galaxy and don’t see the problem quite as bad as you do. Seems the varchars (and sadly the date field) below become objects, but the integer, bigint, and double columns all seem to be OK for me.

```auto
# skipping the creation of session for brevity 

ordersPySbDf = session.sql("select * from tpch.tiny.orders")

print('** cols and type from PyStarburst dataframe \n')
for field in ordersPySbDf.schema.fields:
    print(field.name +" , "+str(field.datatype))

pandasDf = ordersPySbDf.to_pandas()

print('\n\n** cols and type from pandas dataframe (one way) \n')
pandasDf.info(verbose=True)

print('\n\n** cols and type from pandas dataframe (nuther way) \n')
print(pandasDf.dtypes)

```

Output:

```auto
** cols and type from PyStarburst dataframe 

orderkey , type='LongType'
custkey , type='LongType'
orderstatus , size=None type='StringType'
totalprice , type='DoubleType'
orderdate , type='DateType'
orderpriority , size=None type='StringType'
clerk , size=None type='StringType'
shippriority , type='IntegerType'
comment , size=None type='StringType'

** cols and type from pandas dataframe (one way) 

<class 'pandas.core.frame.DataFrame'>
RangeIndex: 15000 entries, 0 to 14999
Data columns (total 9 columns):
 # Column Non-Null Count Dtype  
--- ------ -------------- -----  
 0 orderkey 15000 non-null int64  
 1 custkey 15000 non-null int64  
 2 orderstatus 15000 non-null object 
 3 totalprice 15000 non-null float64
 4 orderdate 15000 non-null object 
 5 orderpriority 15000 non-null object 
 6 clerk 15000 non-null object 
 7 shippriority 15000 non-null int64  
 8 comment 15000 non-null object 
dtypes: float64(1), int64(3), object(5)
memory usage: 1.0+ MB

** cols and type from pandas dataframe (nuther way) 

orderkey int64
custkey int64
orderstatus object
totalprice float64
orderdate object
orderpriority object
clerk object
shippriority int64
comment object
dtype: object

```

Can you try to reproduce what I got? If you get something different, can you run it the same way I did? You can visit [starburst-dataframes-exploration/PyStarburst/notebooks/PlayingWithPandas.ipynb at main · lestermartin/starburst-dataframes-exploration · GitHub](https://github.com/lestermartin/starburst-dataframes-exploration/blob/main/PyStarburst/notebooks/PlayingWithPandas.ipynb) and click on the ‘Open in Colab’ button at the top.