How to get oracle inner join query result in pandas

Using Streamlit
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2

Welcome to the community and thanks for your detailed question! :blush: It could be possible that the error is due to the way you’re merging multiple DataFrames in pandas. In pandas, you can’t merge more than two DataFrames at once using a single pd.merge() call. Instead, you should perform the joins step-by-step, similar to chaining SQL joins. According to this discussion, you should first merge employees and departments on emp_id, then merge the result with itemtab on item_id.

Here’s a concise example based on your data:

import pandas as pd

# Your DataFrames
employees = pd.DataFrame({
    'emp_id': [1, 2, 3],
    'name': ['Alice', 'Bob', 'Charlie']
})

departments = pd.DataFrame({
    'dept_id': [101, 102, 103],
    'emp_id': [2, 3, 4],
    'item_id': [2, 3, 4],
    'dept_name': ['HR', 'IT', 'Finance']
})

itemtab = pd.DataFrame({
    'dept_id': [101, 102, 103, '', '', ''],
    'item_id': [1, 2, 3, 4, 5, 6],
    'item_name': ['computer', 'car', 'bus', 'home', 'flate', 'treain']
})

# Stepwise inner joins
result = pd.merge(employees, departments, on='emp_id', how='inner')
result = pd.merge(result, itemtab, on='item_id', how='inner')
print(result)

This approach should give you the equivalent of your Oracle SQL inner join. If you want more detail or a breakdown of each step, just let me know!

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