1,000 rows · 8 columns
Deliberately messy customers
A thousand customer records broken in every way real data is broken: five date formats, inconsistent casing, padded whitespace, near-duplicate rows, mixed units, sentinel nulls, and encoding damage.
What is in it, and what is wrong with it
This one is a training dummy, not a report. Nothing in it is trustworthy: signup_date appears as ISO, US, European, and two textual formats; country mixes full names and codes and casing; spend mixes dollars and cents in the same column; missing values appear as blank, NULL, N/A, -, and -999. There are 43 near-duplicate records that differ only by whitespace or casing. Cleaning it end-to-end is the exercise.
Schema
| Column | Type | Description |
|---|---|---|
| customer_id | string | Sometimes padded, sometimes not. |
| full_name | string | Inconsistent casing and stray whitespace. |
| string | Some invalid, some with display names attached. | |
| signup_date | string | Five different formats. Do not trust the parser default. |
| country | string | Codes and full names, mixed casing. |
| spend | string | Mixed units, currency symbols, and thousands separators. |
| segment | string | Free text with typos and synonyms. |
| is_active | string | Y/N, true/false, 1/0, and yes/no all appear. |
First twelve rows
| customer_id | full_name | signup_date | country | spend | segment | is_active | |
|---|---|---|---|---|---|---|---|
| CUST-1387 | Aisha Brennan | aisha.brennan@mail.test | NULL | Germany | - | enterprise | N |
| CUST-1943 | omar Brennan | omar.brennan@example.com | 25 Jan 2025 | uk | $100.66 | enterprise | N |
| CUST-1007 | ravi okafor | ravi[at]example.com | 2024-10-18 | Brazil | $273.67 | ENT | 1 |
| CUST-1249 | Leilani da silva | leilani.dasilva@corp.example | Jun 26, 2024 | United Kingdom | $84.38 | Mid-Market | yes |
| CUST-1900 | Marcus Kowalski | marcus.kowalski@example.com | Sep 26, 2024 | germany | NULL | midmarket | true |
| CUST-1841 | Leilani ODWYER | leilani.odwyer@example.com | 19 Jun 2023 | Brazil | 122.09 | Consumer | yes |
| CUST-1433 | tomás ODWYER | toms.odwyer@corp.example | 2024-04-06 | Brazil | USD 139.54 | Enterprise | FALSE |
| CUST-1194 | PRIYA Costa | priya.costa@mail.test | 08.01.2023 | u.s. | $461.54 | smb | false |
| CUST-1466 | ana Nakamura | ana.nakamura@mail.test | 10 Dec 2023 | United States | $341.62 | Mid-Market | no |
| CUST-1116 | Yuki Nguyen | yuki.nguyen@example.com | 05.02.2025 | GB | $242.52 | Consumer | FALSE |
| CUST-1811 | Leilani PATEL | leilani.patel@example.com | 14 Jun 2024 | DE | 136.26 | Mid Market | Y |
| CUST-1580 | Yuki okafor | yuki.okafor@corp.example | Aug 18, 2023 | Brazil | $189.67 | ENT | no |