philosophology wrote:What are c1, c2, and id?
Explain like I'm a 4 year old please 🙂
thank you.
Those are just hypothetical column names, while "a" and "b" are hypothetical table names. In this example, "id" is the column name in both tables for the field which establishes the relationship between the tables, possibly an auto-incremented, integer, primary key field in table "a", which is then used in table "b" to link each record to the corresponding record in table "a". So in this example, the two tables would consist of (at least):
Table a
------------
id INT AUTO_INCREMENT PRIMARY KEY
c1
c2
Table b
------------
id INT
c1 (not necessarily the same as the same column in table a)
c2 (ditto)