Expand on readme to link to examples within tpch folder

Author: timsaucer

examples/README.md

@@ -59,3 +59,60 @@ Within the subdirectory `tpch` there are 22 examples that reproduce queries in
 the TPC-H specification. These include realistic data that can be generated at
 arbitrary scale and allow the user to see use cases for a variety of data frame
 operations.
+
+In the list below we describe which new operations can be found in the examples.
+The queries are designed to be of increasing complexity, so it is recommended to
+review them in order. For brevity, the following list does not include operations
+found in previous examples.
+
+- [Convert CSV to Parquet](./tpch/convert_data_to_parquet.py)
+    - Read from a CSV files where the delimiter is something other than a comma
+    - Specify schema during CVS reading
+    - Write to a parquet file
+- [Pricing Summary Report](./tpch/q01_pricing_summary_report.py)
+    - Aggregation computing the maximum value, average, sum, and number of entries
+    - Filter data by date and interval
+    - Sorting
+- [Minimum Cost Supplier](./tpch/q02_minimum_cost_supplier.py)
+    - Window operation to find minimum
+    - Sorting in descending order
+- [Shipping Priority](./tpch/q03_shipping_priority.py)
+- [Order Priority Checking](./tpch/q04_order_priority_checking.py)
+    - Aggregating multiple times in one data frame
+- [Local Supplier Volume](./tpch/q05_local_supplier_volume.py)
+- [Forecasting Revenue Change](./tpch/q06_forecasting_revenue_change.py)
+    - Using collect and extracting values as a python object
+- [Volume Shipping](./tpch/q07_volume_shipping.py)
+    - Finding multiple distinct and mutually exclusive values within one dataframe
+    - Using `case` and `when` statements
+- [Market Share](./tpch/q08_market_share.py)
+    - The operations in this query are similar to those in the prior examples, but
+      it is a more complex example of using filters, joins, and aggregates
+    - Using left outer joins
+- [Product Type Profit Measure](./tpch/q09_product_type_profit_measure.py)
+    - Extract year from a date
+- [Returned Item Reporting](./tpch/q10_returned_item_reporting.py)
+- [Important Stock Identification](./tpch/q11_important_stock_identification.py)
+- [Shipping Modes and Order](./tpch/q12_ship_mode_order_priority.py)
+    - Finding non-null values using a boolean operation in a filter
+    - Case statement with default value
+- [Customer Distribution](./tpch/q13_customer_distribution.py)
+- [Promotion Effect](./tpch/q14_promotion_effect.py)
+- [Top Supplier](./tpch/q15_top_supplier.py)
+- [Parts/Supplier Relationship](./tpch/q16_part_supplier_relationship.py)
+    - Using anti joins
+    - Using regular expressions (regex)
+    - Creating arrays of literal values
+    - Determine if an element exists within an array
+- [Small-Quantity-Order Revenue](./tpch/q17_small_quantity_order.py)
+- [Large Volume Customer](./tpch/q18_large_volume_customer.py)
+- [Discounted Revenue](./tpch/q19_discounted_revenue.py)
+    - Creating a user defined function (UDF)
+    - Convert pyarrow Array to python values
+    - Filtering based on a UDF
+- [Potential Part Promotion](./tpch/q20_potential_part_promotion.py)
+    - Extracting part of a string using substr
+- [Suppliers Who Kept Orders Waiting](./tpch/q21_suppliers_kept_orders_waiting.py)
+    - Using array aggregation
+    - Determining the size of array elements
+- [Global Sales Opportunity](./tpch/q22_global_sales_opportunity.py)