Inner join returns only those records from the tables that match the specified condition and hides other rows and columns. In simple words, it fetches rows when there is at least one match of rows between the tables is found. INNER JOIN keyword joins the matching records from two tables. It is assumed as a default join, so it is optional to use the INNER keyword with the query.
The below visual representation explain this join more clearly:
SQL Interview Questions and Answers
The following syntax illustrates the INNER JOIN:
SELECT column_lists
FROM table1
INNER JOIN table2 ON join_condition1
INNER JOIN table3 ON join_condition2
...;