← GIS / Urban-Data Analytics Lead
publisheddata

SQL, PostGIS & large-data handling

Working with data that no longer fits in a spreadsheet — property tax rolls, census records, sensor feeds, a state's full parcel layer — and asking spatial questions of it in the database rather than exporting it first.

What you will be able to answer

A city's property tax roll and its parcel layer are two files nobody can open together, and the commissioner wants collection by ward. How do you answer that without exporting anything?

Load both into the database with column types that match the data, join the roll to the parcels on the property key, then combine a spatial predicate with grouping so collection is summed per ward in a single query rather than by hand. A left join is the deliberate choice — it keeps the tax records that match no parcel, and those unmatched rows are usually the finding rather than an error to discard. A spatial index on the parcel geometry is what keeps the join workable at that size, and QGIS can read the query result as a live layer instead of another exported shapefile.

Concepts
13
Selected clips
55m 42s
Employers use it
18

One payment

₹99

The videos are free

This is what you pay for

Compared → kept
39 → 13
Full videos → selected
3h 20m → 55m 42s
Concepts
13

Course outline

Learn from selected clips, concept by concept

Concept 1

When a spreadsheet stops being the right tool

free

Concept 1 · When a spreadsheet stops being the right tool

0:00 / 0:29

Concept 2

What SQL is, and what a query actually looks like

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After: when-a-spreadsheet-breaks

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4m 37s kept
Video review
1 compared

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Concept 3

Tables, rows, columns and keys

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After: what-sql-is

A foreign key linking an employee table to a department table, with referential integrity visible in the data.

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6m 48s kept
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Concept 4

Your first real query: SELECT, WHERE, ORDER BY

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After: tables-and-keys

SELECT, multi-condition WHERE, ORDER BY and LIMIT executed live with output on screen.

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6m 11s kept
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Concept 5

Counting and summarising with GROUP BY

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After: select-where

GROUP BY with HAVING, filtering the groups rather than the rows.

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4m 48s kept
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3 compared

Video title and channel appear once unlocked.

Concept 6

JOINs: combining tables

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After: aggregation

A LEFT JOIN executed so unmatched rows survive as NULLs you can actually see.

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3m 40s kept
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Video title and channel appear once unlocked.

Concept 7

Building a query in steps with CTEs

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After: joins

One complex query decomposed into named stages, set against the nested version it replaces.

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4m 01s kept
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Concept 8

Why a query gets slow, and what an index does

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After: joins

Execution plans before and after an index, plus what that index costs on writes.

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2m 45s kept
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Video title and channel appear once unlocked.

Concept 9

Getting your data into the database

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After: tables-and-keys

A table created with matching column types, then a CSV imported into it.

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5m 28s kept
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Video title and channel appear once unlocked.

Concept 10

PostGIS: a geometry column in your table

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After: loading-data, select-where

ST_SRID and ST_AsText run against a geometry column to see what is actually stored.

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3m 55s kept
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3 compared

Video title and channel appear once unlocked.

Concept 11

Asking spatial questions in SQL

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After: postgis-geometry

ST_Intersects joining boundary polygons to a hex grid in a single query.

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1m 24s kept
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Concept 12

Spatial joins and summarising by area

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After: spatial-predicates, aggregation

ST_Contains combined with GROUP BY to count points inside each polygon.

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6m 10s kept
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3 compared

Video title and channel appear once unlocked.

Concept 13

Using the database from QGIS

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After: spatial-predicates

A PostGIS connection created in QGIS, and a spatial layer pushed straight into the database.

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Clip retained
2m 24s kept
Video review
3 compared

Video title and channel appear once unlocked.

Selection criteria

  • Teaches one concept end to end, without needing the rest of the video
  • Speaker does this work, or teaches it to people who will
  • Transfers to Indian practice, or is marked where it does not
  • Audio and screen legible on a phone, on mobile data

What was rejected

10 candidates did not meet the course criteria.

  • The video uses animated text slides rather than demonstrating actual database or spreadsheet software in action.
  • Only covers primary keys and candidate keys; does not cover foreign keys or multi-table relationships.
  • covers aggregate functions without GROUP BY at all
  • This video explains how to read execution plans and join orders in Oracle, but does not cover what an index is or how indexes speed up queries.
  • clicks through an import wizard with no discussion of types or failures
  • clicks through an import wizard with no discussion of types or failures
  • The video demonstrates ST_Centroid and ST_Transform to convert polygon data to points rather than using spatial predicates like ST_Within or ST_Intersects to answer spatial relation questions.
  • No SQL queries written or shown in the video
  • The video contains auto-generated slides from a Q&A forum post and does not teach spatial joins or spatial aggregation.
  • performs the spatial join without any aggregation step

Where this skill is used

GIS / Urban-Data Analytics Lead

Spatial-data and analytics roles — building GIS systems, remote-sensing pipelines, urban dashboards, and data products for planning clients, authorities, and tech/geospatial firms. Strong demand where planning meets data. Specialisation tags: Urban, Regional, Environmental (cross-cutting).

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Planner — TCPO / MoHUA / NCRPB (Central)

Central-government planning at the Town & Country Planning Organisation (under MoHUA) and bodies like the National Capital Region Planning Board. You work on national urban policy, regional plans, model guidelines, and inter-state coordination. Seats are very limited, UPSC/TCPO notifications are intermittent, and entry is prestigious. Specialisation tags: Urban, Regional, Infrastructure.

10 mapped employers

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