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Lesson 15.3 · garden_shop
Lesson 15.3

SQL INTERSECT

INTERSECT finds the overlap between two compatible result sets.

INTERSECT returns rows that appear in both result sets. It is a compact way to answer "what values do these two groups have in common?"

Like UNION, it compares the selected rows, so keep the selected columns focused on the value you want to compare.

Pattern 
select value_column
from first_table
intersect
select value_column
from second_table

Compare the same shape

Both sides need the same number of columns. If you select a customer name on one side and a supplier name on the other, you are comparing names, not the states they share.

Schema · Garden Shop Tables · customers, suppliers 2 tables
Table · customers

One row per customer. Some customers have no phone on file.

9 columns · 20 rows
customer_id int first_name text last_name text email text phone text city text state text signup_date date is_active bool
Table · suppliers

One row per supplier. Some suppliers have no contact email.

4 columns · 6 rows
supplier_id int supplier_name text contact_email text state text
Syntax reference
Need syntax details? See the SQL set operations reference
Your task

Return the state values that appear in both customers and suppliers, sorted alphabetically.

·

Run your query to inspect the result.

Expected answer
  • Columns: state.
  • Rows: states found in both customers and suppliers.
  • INTERSECT returns the overlap between two compatible result sets.
Next · 15.4 EXCEPT →

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