BigQuery SQL and pricing model in GCP - Step-by-Step Execution

Process Flow - BigQuery SQL and pricing model

Write SQL Query

↓

Submit Query to BigQuery

↓

BigQuery Scans Data

↓

Calculate Data Processed (in bytes)

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Apply Pricing Model

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Return Query Results

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Bill User Based on Data Processed

This flow shows how a SQL query is submitted to BigQuery, how data scanned is calculated, pricing applied, and results returned.

Execution Sample

GCP

SELECT name, age FROM `project.dataset.table` WHERE age > 30;

This SQL query selects names and ages from a table where age is greater than 30.

Process Table

Step	Action	Data Scanned (GB)	Pricing Calculation	Result
1	Submit SQL query	0	No cost yet	Query accepted
2	BigQuery scans table data	2.5	2.5 GB * $5 per TB = $0.0122	Data scanned calculated
3	Apply on-demand pricing	2.5	Cost = $0.0122	Cost calculated
4	Return query results	2.5	Cost charged to user	Results delivered
5	End	2.5	Billing complete	Query finished

💡 Query completes after scanning 2.5 GB, cost calculated and charged accordingly.

Status Tracker

Variable	Start	After Step 2	After Step 3	Final
Data Scanned (GB)	0	2.5	2.5	2.5
Cost (USD)	0	0	0.0122	0.0122

Key Moments - 3 Insights

Why does the cost depend on data scanned, not query complexity?

BigQuery charges based on the amount of data processed, not how complex the SQL is. See execution_table step 2 where data scanned is calculated first, then cost applied.

What happens if the query scans less data?

Cost decreases proportionally because pricing is per GB scanned. This is shown in execution_table step 3 where cost is calculated from data scanned.

Is the user billed before or after results are returned?

Billing happens after data scanned is calculated but before results are returned, as shown in execution_table steps 3 and 4.

Visual Quiz - 3 Questions

Look at the execution_table, what is the data scanned at step 2?

A 2.5 GB

B 0 GB

C 5 GB

D 1 GB

💡 Hint

Check the 'Data Scanned (GB)' column at step 2 in execution_table.

At which step is the cost calculated?

A Step 1

B Step 3

C Step 4

D Step 5

💡 Hint

Look at the 'Pricing Calculation' column in execution_table for when cost is computed.

If the data scanned was 5 GB instead of 2.5 GB, how would the cost change?

A It would halve

B It would stay the same

C It would double

D It would be zero

💡 Hint

Cost is proportional to data scanned as shown in execution_table step 3.

Concept Snapshot

BigQuery SQL queries scan data in tables.
Pricing is based on data scanned (GB), not query complexity.
On-demand pricing charges $5 per TB scanned.
Cost = Data scanned (GB) * $5 / 1024.
Results returned after billing calculation.
Optimize queries to scan less data to save cost.

Full Transcript

This visual execution shows how a BigQuery SQL query is processed and billed. First, the query is submitted. BigQuery scans the data needed to answer the query, measuring how many gigabytes are processed. Then, it calculates the cost based on the data scanned using the on-demand pricing model, which charges $5 per terabyte. After cost calculation, the query results are returned to the user. The user is billed based on the data scanned. This helps understand that cost depends on data volume scanned, not on how complex the SQL query is. Optimizing queries to scan less data reduces cost.