01
How do you handle a dataset with 30% missing values in a key column?
Show answer
Understand why it is missing, consider imputation or a missing flag, test sensitivity, and talk to data owners about fixing collection if it is systematic.
Delhivery Data Analytics Interview Questions & Answers
Curated interview practice questions with answers. These are practice scenarios, not a verified list of past interview questions.
About Delhivery hiring for Data Analytics roles
Delhivery is an Indian logistics and supply chain company that provides parcel delivery, freight, warehousing and fulfilment services for e-commerce and enterprise clients. It runs a large network of hubs and uses technology for route planning, tracking and automation. It hires software engineers, data scientists, data analysts and operations professionals.
For Data Analytics roles, this Delhivery practice set focuses most on Python for Analysis (7), Web & Marketing Analytics (5), Data Cleaning (4), SQL (4). It has 1 easy, 31 medium, 8 hard questions, so you can start easy and work up to the harder ones.
- Company type
- E-commerce & consumer tech
- Headquarters
- Gurugram, India
- Main India offices
- Gurugram, Bengaluru
Delhivery Data Analytics interview process
- Online coding or analytics assessment
- Technical round 1
- Technical round 2 (design or case)
- Hiring manager round
Typical pattern based on public candidate experiences. Rounds vary by role, team and year.
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02
Write Python code to test whether conversion differs between control and treatment.
Show answer
from statsmodels.stats.proportion import proportions_ztest, proportion_confint
conversions = [1180, 1295] # control, treatment
visitors = [30000, 30100]
z, p = proportions_ztest(conversions, visitors)
print(f'z = {z:.2f}, p = {p:.4f}')
for c, n in zip(conversions, visitors):
low, high = proportion_confint(c, n, method='wilson')
print(f'rate {c/n:.3%} 95% CI {low:.3%} to {high:.3%}')
03
How do you pivot rows into columns in SQL, for example sales by quarter as columns?
Show answer
SELECT region,
SUM(CASE WHEN quarter = 'Q1' THEN amount ELSE 0 END) AS q1,
SUM(CASE WHEN quarter = 'Q2' THEN amount ELSE 0 END) AS q2,
SUM(CASE WHEN quarter = 'Q3' THEN amount ELSE 0 END) AS q3,
SUM(CASE WHEN quarter = 'Q4' THEN amount ELSE 0 END) AS q4
FROM sales
GROUP BY region;
-- conditional aggregation works in every database; some also offer PIVOT
04
Traffic suddenly doubled from one city, with near-zero engagement time and no conversions. What is happening and what do you do?
Show answer
This is very likely bot or spam traffic, or a misfiring tag. Check the user agents, IP ranges, hostnames, screen resolutions and landing pages for that traffic. If it is bots, exclude it with filters or data segments in analytics and in your reporting layer, and inform the web team so they can block it. Then restate the affected dashboard numbers, because bots inflate sessions and pull down conversion rate.
05
How do you improve Power BI report performance?
Show answer
Use a star schema, remove unused columns, prefer measures, reduce visuals per page, limit high-cardinality fields and use aggregations or incremental refresh.
06
A stakeholder says the Power BI report shows different revenue than their Excel file. How do you troubleshoot?
Show answer
I would first agree on definitions: gross or net, including tax or returns, order date or invoice date. Then compare one small slice, such as one month and one region, in both. I check filters on the report and page, relationships that drop unmatched rows, refresh time versus the Excel extract time, and duplicate rows. Once the gap is explained, I document the definition in the report so the question does not repeat.
07
Your scheduled Python report failed silently and nobody noticed for a week. How do you make it reliable?
Show answer
Add logging to a file or central log, wrap the main steps in try and except that send an alert by email or chat on failure, and exit with a non-zero code so the scheduler marks the job failed. Add data checks, such as row counts above a minimum and no missing dates, before sending output. Use a proper scheduler or orchestrator with retries, and include the data date in every report.
08
Which KPIs would you track for an e-commerce app?
Show answer
DAU/MAU, conversion rate, average order value, cart abandonment, retention/churn, CAC, LTV, return rate and NPS.
09
Write Python code to extract valid 10-digit Indian mobile numbers from a messy text column.
Show answer
import re
pattern = re.compile(r'(?:\+?91[\s-]?|0)?([6-9]\d{9})')
def get_mobile(text):
if not isinstance(text, str):
return None
digits = re.sub(r'[\s()-]', '', text)
m = pattern.search(digits)
return m.group(1) if m else None
df['mobile'] = df['contact'].apply(get_mobile)
10
Email open rates suddenly jumped from 22% to 45% without any campaign change. Should you celebrate?
Show answer
No. Privacy features in some mail apps pre-load email images, which fires the open tracking pixel even if the person never reads the email, so open rates get inflated. Check opens by email client to confirm. Move reporting towards clicks, click-to-send rate, conversions and unsubscribes, which reflect real behaviour, and avoid using opens alone to pick winning subject lines or to define engaged subscribers.
11
What is the difference between melt and pivot?
Show answer
melt converts wide data to long format; pivot converts long data to wide, and they are used to reshape data for analysis or charts.
12
Your Top 10 products filter in Tableau ignores the category filter. Why, and how do you fix it?
Show answer
A context filter is applied before other dimension filters and before FIXED LOD calculations, creating a smaller dataset the rest of the view works on. Use it when a Top N filter should operate within a selected category, for example top 10 products within Electronics, or when a FIXED LOD must respect a filter. Add a filter to context from its right-click menu; it turns grey. Too many context filters can hurt performance.
13
What is the grain of a fact table and why should you decide it first?
Show answer
The grain is the exact meaning of one row in a fact table, such as one order line, one daily store total or one monthly account balance. You decide it first because it controls which dimensions can join, which measures are valid and how totals behave. Mixing grains in one table, for example order lines and order-level shipping charges, causes double counting. Always state the grain in one sentence before adding columns.
14
A retail chain asks you which of its 120 stores it should close. How do you approach it?
Show answer
Clarify the goal first: profit, cash or market share. Build a store-level dataset with revenue, contribution margin after rent and staff, trend over 24 months, footfall, catchment demographics and cannibalisation with nearby stores. Separate structural losers from stores that are new or temporarily disrupted. Estimate how much revenue would shift to nearby stores or online if a store closes. Present a shortlist with scenarios and risks, not a single answer.
15
Explain Matplotlib vs Seaborn.
Show answer
Matplotlib is the low-level plotting library with full control; Seaborn builds on it with attractive statistical charts and simpler syntax.
16
How do you detect outliers?
Show answer
Visually with a box plot, with the IQR rule (below Q1 − 1.5×IQR or above Q3 + 1.5×IQR) or a z-score above 3. Then decide with the business whether to cap, remove or keep them.
17
You must present to the sales team that they missed their quarterly target by 18%. How do you handle it?
Show answer
Lead with the fact clearly, then show where the gap came from, such as which regions, products or deal stages, so it becomes actionable rather than a blame session. Separate controllable causes like lower conversion from uncontrollable ones like a delayed product launch. Highlight what did work, and end with two or three specific actions and the metrics to track them. Share the numbers with sales leaders privately first, to avoid surprises.
18
What is the difference between frequentist and Bayesian A/B testing?
Show answer
Frequentist testing asks how surprising the data would be if there were no difference, and gives p-values and confidence intervals with a fixed sample size. Bayesian testing combines a prior with the data to give a probability that treatment beats control and the expected loss of choosing it. Bayesian results are easier for business users to read, but still depend on priors and still need sensible stopping rules.
19
Write SQL to calculate monthly customer churn rate.
Show answer
WITH active AS (
SELECT DISTINCT customer_id,
DATE_TRUNC('month', order_date) AS month
FROM orders
)
SELECT a.month,
COUNT(*) AS active_customers,
COUNT(*) - COUNT(n.customer_id) AS churned_next_month,
ROUND(100.0 * (COUNT(*) - COUNT(n.customer_id)) / COUNT(*), 1) AS churn_pct
FROM active a
LEFT JOIN active n
ON n.customer_id = a.customer_id
AND n.month = a.month + INTERVAL '1 month'
GROUP BY a.month
ORDER BY a.month;
20
Write a DAX measure for a KPI card showing achievement against target and a colour for conditional formatting.
Show answer
Achievement % =
DIVIDE([Total Sales], [Sales Target])
KPI Colour =
VAR a = [Achievement %]
RETURN
SWITCH(
TRUE(),
ISBLANK(a), "#9E9E9E",
a >= 1, "#2E7D32",
a >= 0.9, "#F9A825",
"#C62828"
)
-- apply KPI Colour via Format > Callout value > fx > Field value
21
What is an enterprise bus matrix?
Show answer
A bus matrix is a planning grid with business processes as rows, such as orders, shipments and returns, and conformed dimensions as columns, such as date, customer, product and warehouse. A tick shows which dimensions each process uses. It helps prioritise which fact tables to build, shows which dimensions must be shared and conformed first, and gives leaders a one-page roadmap of the warehouse without technical detail.
22
What is the LAMBDA function in Excel and when would you use it?
Show answer
LAMBDA lets you write a custom, reusable function with formulas only, no VBA. You define it, for example =LAMBDA(price, rate, price*(1+rate)), and save it in the Name Manager as AddGST, then call =AddGST(B2, 18%) anywhere. Helper functions like MAP, REDUCE, SCAN and BYROW pair with it for array logic. Use it when a complex calculation repeats across a workbook, so the logic lives in one tested place.
23
You loaded a month of sales into the warehouse. How do you check the load is complete and correct?
Show answer
Reconcile against the source: compare row counts, total amount, and counts by day and by store between source and target. Check for duplicate keys, nulls in mandatory columns, and dates outside the expected month. Compare with the previous month to spot big unexplained jumps. Spot-check a few individual transactions end to end. Automate these checks so each future load produces a small pass or fail report.
24
Tell me about a time you worked with a marketing team to improve a campaign using data.
Show answer
Situation: a lead generation campaign had a high cost per lead and sales said leads were poor. Task: find what to change. Action: I joined ad data with CRM outcomes and found two audience segments produced most leads but almost no closed deals, while one smaller segment converted well. Result: we moved budget to that segment and changed the form questions; cost per qualified lead fell about 30% in six weeks.
25
Write pandas code to fill missing values in a column with the median of each group.
Show answer
# Fill missing delivery_days with the median for that city
df['delivery_days'] = (
df['delivery_days']
.fillna(df.groupby('city')['delivery_days'].transform('median'))
)
# Rows in a city with no values at all stay NaN; fall back to overall median
df['delivery_days'] = df['delivery_days'].fillna(df['delivery_days'].median())
26
Write pandas code for a pivot table of sales by region and category with sum and count.
Show answer
import pandas as pd
summary = pd.pivot_table(
df,
index='region',
columns='category',
values='sales',
aggfunc=['sum', 'count'],
fill_value=0,
margins=True # adds an All row and column
)
print(summary)
27
Write SQL to show each category's percentage share of total revenue.
Show answer
SELECT category,
SUM(amount) AS revenue,
ROUND(100.0 * SUM(amount)
/ SUM(SUM(amount)) OVER (), 2) AS pct_share
FROM sales
GROUP BY category
ORDER BY revenue DESC;
-- SUM(SUM(amount)) OVER () is the grand total across all groups
28
What does apply do in pandas and why can it be slow?
Show answer
apply runs a Python function on each row or column of a DataFrame, or each value of a Series. It is flexible but slow on large data because it loops in Python rather than using optimised C code. For example, df['total'] = df['qty'] * df['price'] is far faster than an apply with a lambda. Prefer vectorised operations, np.where, np.select, map with a dictionary, or string accessor methods first.
29
How do you find duplicate rows in a table?
Show answer
SELECT col, COUNT(*) FROM t GROUP BY col HAVING COUNT(*) > 1; use ROW_NUMBER() partitioned by the key to delete extras.
30
Sales dropped 20% last month. How will you analyse it?
Show answer
Confirm data accuracy first → break down by region, product, channel and customer segment → compare with seasonality and last year → check pricing, stock-outs, marketing changes and funnel conversion → present the root causes with clear charts.
31
Write Python code to extract UTM source, medium and campaign from a column of landing page URLs.
Show answer
import pandas as pd
from urllib.parse import urlparse, parse_qs
def get_utms(url):
params = parse_qs(urlparse(str(url)).query)
return pd.Series({
'source': params.get('utm_source', ['(direct)'])[0].lower(),
'medium': params.get('utm_medium', ['(none)'])[0].lower(),
'campaign': params.get('utm_campaign', ['(not set)'])[0].lower(),
})
df[['source', 'medium', 'campaign']] = df['landing_url'].apply(get_utms)
32
What is Power Pivot and the Excel Data Model?
Show answer
The Data Model is an in-memory columnar store inside Excel that holds several related tables, and Power Pivot is the interface to manage it. Instead of flattening data with VLOOKUPs, you load fact and dimension tables, create relationships and write DAX measures. It handles millions of rows that would not fit on a sheet, and PivotTables built on it can slice across tables. It is the same engine idea that Power BI uses.
33
Write SQL to generate a simple date dimension for 2026.
Show answer
-- PostgreSQL syntax
CREATE TABLE dim_date AS
SELECT
TO_CHAR(d, 'YYYYMMDD')::INT AS date_key,
d::DATE AS full_date,
EXTRACT(YEAR FROM d) AS year,
EXTRACT(QUARTER FROM d) AS quarter,
EXTRACT(MONTH FROM d) AS month_no,
TO_CHAR(d, 'Mon') AS month_name,
TO_CHAR(d, 'Dy') AS weekday,
EXTRACT(ISODOW FROM d) IN (6, 7) AS is_weekend
FROM GENERATE_SERIES(DATE '2026-01-01', DATE '2026-12-31', INTERVAL '1 day') AS d;
34
Tell me about a time you handled a request for access to sensitive data.
Show answer
Situation: a regional manager asked for a salary-level export of all employees to plan hiring. Task: help without breaking data policy. Action: I clarified the actual need, which was headcount cost by grade and location, checked with HR on access rules, and built a Power BI view with aggregated costs and row-level security limiting each manager to their region. Result: the manager got what was needed and no individual salaries were exposed.
35
Write a Tableau calculation to find each customer's first purchase date and flag new versus repeat orders.
Show answer
// First Purchase Date
{ FIXED [Customer ID] : MIN([Order Date]) }
// Order Type
IF [Order Date] = [First Purchase Date]
THEN 'New'
ELSE 'Repeat'
END
// Cohort Month for retention analysis
DATETRUNC('month', [First Purchase Date])
36
Your pandas script takes 40 minutes on 10 million rows. How do you speed it up?
Show answer
First profile to find the slow step instead of guessing. Common fixes: replace row-wise apply and loops with vectorised operations, convert repeated strings to category dtype, downcast numeric types, read only needed columns with usecols, and filter early. Push heavy joins and aggregations into SQL. If it is still slow, use a columnar engine such as DuckDB or Polars, or store intermediate data as Parquet instead of CSV.
37
Explain correlation vs regression.
Show answer
Correlation shows the strength and direction of association; regression builds an equation to predict one variable from others.
38
Your NOT IN query unexpectedly returns zero rows. Why might that happen, and how do EXISTS and IN differ?
Show answer
IN checks whether a value is in a list or subquery result; EXISTS checks whether a subquery returns at least one row and stops at the first match. Results are the same in most cases, and modern optimisers often run them similarly. The big difference is NOT IN with NULLs: if the subquery returns any NULL, NOT IN returns no rows. NOT EXISTS behaves correctly, so prefer it for anti-joins.
39
Site conversion rate rose from 2.0% to 2.4%, but total revenue stayed flat. What would you check?
Show answer
Check the components: sessions may have fallen, for example after cutting paid campaigns, which removes low-intent traffic and lifts the rate without new sales. Average order value may have dropped because of discounts or a mix shift towards cheaper products. Also check whether conversion definitions or tracking changed. Revenue equals sessions times conversion rate times AOV, so break down the change across those three factors by channel.
40
What is the difference between dimensions and measures in Tableau?
Show answer
Dimensions are qualitative fields such as region, product or date that slice data into groups and create headers. Measures are quantitative fields such as sales or profit that get aggregated, by default with SUM. Dragging a dimension to rows creates one row per member; dragging a measure creates an axis. A numeric field like customer ID should be converted to a dimension so it is not summed.
Tips to crack the Delhivery Data Analytics interview
- Learn logistics basics such as first mile, last mile, hub operations and shipment tracking to discuss the domain.
- Practise optimisation-style problems and graph algorithms, which connect well to routing and network planning work.
- For analyst roles, revise SQL and Excel, and prepare to analyse delivery delays or cost per shipment in a case.
- Keep a one-minute story ready for every project on your CV: problem, your part, tools, result.
- Practise the hard questions on this page aloud; Delhivery interviewers usually ask follow-ups on your first answer.
Frequently asked questions
How many rounds are there in the Delhivery Data Analytics interview?
Candidates usually go through 4 stages: Online coding or analytics assessment; Technical round 1; Technical round 2 (design or case); Hiring manager round. The exact rounds change with the role, team, location and your experience, so confirm the process with the recruiter.
Which topics should I prepare for the Delhivery Data Analytics interview?
This practice set leans on Python for Analysis (7), Web & Marketing Analytics (5), Data Cleaning (4), SQL (4). Revise those first, then practise explaining one or two of your own projects end to end, because most Delhivery interviewers ask you to walk through real work.
Are these the exact questions asked at Delhivery?
No. These are curated practice questions that match the skills and difficulty usually tested in e-commerce & consumer tech interviews like Delhivery's. They are not a leaked or verified list of past questions.
Where does Delhivery hire Data Analytics professionals in India?
Delhivery has large teams in Gurugram, Bengaluru. Openings and locations change often, so check the Delhivery careers page and filter by city and experience.
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