Implicit Joins
In simple terms, the "implicit join" simply lists the tables for joining (mostly using the FROM clause of the SELECT statement) as well as it uses commas to separate them.
Implicit Joins Example
SELECT *
FROM employees, departments
WHERE employees.Department_no = departments.Department_no;
Explicit Joins
In simple terms, the "explicit join" uses the JOIN keyword to join two or more tables and the ON keyword to specify the predicates for the join.
Implicit Joins Example
SELECT *
FROM employees JOIN departments
ON employees.DepartmentID = departments.DepartmentID;
The explicit join is easier to read as well figure out what's happening in the query just by looking at it. The implicit syntax is a bit difficult and more prone to errors and is outdated.
differences Explicit Implicit JOIN SQL JOIN