SQL INNER JOIN

The INNER JOIN command returns all rows that have matching values in both tables and omits non-matching rows.

Syntax

SELECT
  table_A.this_column,
  table_A.that_column,
  table_B.this_column,
  table_B.that_column,
FROM table_A
INNER JOIN table_B
  ON table_A.this_value = table_B.this_value;

One or more matching columns can be selected and joined from table_A and table_B based on matching column values between tables in the ON clause.

Example

The following example creates a result set of every row where the student_id matches in both tables and only includes last_name, first_name, and both GPAs:

SELECT
  students.last_name,
  students.first_name,
  students.overall_gpa,
  transfer_data.overal_gpa
FROM students
INNER JOIN transfer_data
  ON students.student_id = transfer_data.student_id;

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