File History Snapshot (2025-12-06T14:39:36.076Z)
USER
  hi! if I wanted to see what thetop Warehouse was for deliveries in 2023, and then generates a table which Compares all warehouses against that one, showing a percentage difference in deliveries against the top one, what would that look like?
ASSISTANT
  Hi! Great question! This is a nice example of using a **subquery** (or CTE) to find a reference value, then comparing everything else against it.
  
  Let me first check what data we have for 2023:
  Tokens: in=2 out=1 cache=14929
ASSISTANT
Tool: Bash
  (toolu_013nAxCfkhH4AYgHtmnfGUvd)
    command: mariadb practice -e "SELECT YEAR(report_date) as year, COUNT(*) as records, SUM(total_shipments) as total_shipments FROM daily_delivery_metrics GROUP BY YEAR(report_date) ORDER BY year"
    description: Check available years in delivery data
  Tokens: in=2 out=179 cache=14929
Result
  (toolu_013nAxCfkhH4AYgHtmnfGUvd)
    year	records	total_shipments
    2023	3646	27524
    2024	3657	27452
ASSISTANT
  We have 2023 data. Now let me build the query and show you how it works:
  Tokens: in=0 out=1 cache=25838
ASSISTANT
Tool: Bash
  (toolu_0186L2r2TDw5qEsXh3vHg1xJ)
    command: mariadb practice -e "
    -- First, let's see the top warehouse for 2023
    SELECT 
        warehouse_id,
        warehouse_name,
        SUM(total_shipments) AS total_deliveries
    FROM daily_delivery_metrics
    WHERE YEAR(r...
    description: Find top warehouses for 2023
  Tokens: in=0 out=194 cache=25838
Result
  (toolu_0186L2r2TDw5qEsXh3vHg1xJ)
    warehouse_id	warehouse_name	total_deliveries
    7	Seattle Gateway	2832
    6	Portland Terminal	2778
    2	San Diego Center	2775
    5	San Francisco Bay	2766
    9	Salt Lake Depot	2762
ASSISTANT
  Seattle Gateway is the top warehouse with 2,832 deliveries. Now here's the full query that compares all warehouses against it:
  Tokens: in=0 out=1 cache=26057
ASSISTANT
Tool: Bash
  (toolu_01N4wk1uzkzrpsxXXiHjrg42)
    command: mariadb practice -e "
    WITH warehouse_totals AS (
        -- Get total deliveries per warehouse for 2023
        SELECT 
            warehouse_id,
            warehouse_name,
            SUM(total_shipments) AS total_deli...
    description: Compare all warehouses to top performer
  Tokens: in=0 out=361 cache=26057
Result
  (toolu_01N4wk1uzkzrpsxXXiHjrg42)
    warehouse_name	total_deliveries	top_deliveries	pct_diff_from_top
    Seattle Gateway	2832	2832	0.0
    Portland Terminal	2778	2832	-1.9
    San Diego Center	2775	2832	-2.0
    San Francisco Bay	2766	2832	-2.3
    Salt Lake Depot	2762	2832	-2.5
    Fresno Valley	2745	2832	-3.1
    Las Vegas Fulfillment	2741	2832	-3.2
    Denver Mountain	2726	2832	-3.7
    Phoenix Distribution	2716	2832	-4.1
    Los Angeles Hub	2683	2832	-5.3
ASSISTANT
  Here's what the query does:
  
  **Key Concepts:**
  
  1. **CTE (Common Table Expression)** - The `WITH ... AS` blocks create temporary named result sets:
     - `warehouse_totals` - calculates each warehouse's total
     - `top_warehouse` - finds the maximum value
  
  2. **CROSS JOIN** - Combines every row from `warehouse_totals` with the single row from `top_warehouse`, so each warehouse row has access to `max_deliveries`
  
  3. **Percentage formula**: `((value - reference) / reference) * 100`
     - Negative means below the top warehouse
     - 0% is the top warehouse itself
  
  Would you like me to explain any part in more detail? I can open a pane showing this step-by-step with intermediate results if that would help!
  Tokens: in=0 out=190 cache=26319
File History Snapshot (2025-12-06T14:41:47.073Z)
USER
  hi! if I wanted to see what thetop Warehouse was for deliveries in 2023, and then generates a table which Compares all warehouses against that one, showing a percentage difference in deliveries against the top one, what would that look like?
ASSISTANT
  Hi! Great question! This is a nice exercise in SQL that combines a few concepts: aggregation, subqueries, and percentage calculations.
  
  Let me first check what data we have for 2023:
  Tokens: in=2 out=1 cache=17760
ASSISTANT
Tool: Bash
  (toolu_012VXADb5cmagAef87TtjqmA)
    command: ~/bin/mariadb practice -e "SELECT MIN(report_date), MAX(report_date) FROM daily_delivery_metrics WHERE YEAR(report_date) = 2023"
    description: Check 2023 data availability
  Tokens: in=2 out=160 cache=17760
Result
  (toolu_012VXADb5cmagAef87TtjqmA)
    MIN(report_date)	MAX(report_date)
    2023-01-01	2023-12-31
ASSISTANT
  We have the full year. Now let me build the query step by step:
  Tokens: in=0 out=1 cache=26064
USER
  [Request interrupted by user]
