Joining Two Tablees

Two tables $A$ and $B$ are joined by a comma to yield all combos of a row from A and a row from B.

CREATE TABLE dogs AS
    SELECT "abraham" AS name, "long" AS fur UNION
    

Example: Grandparents

String Expressions

String values can be combined to form longer strings

sqlite> SELECT "hello," || "world";
hello, world

Basic Sring Manipulation is built into SQL, but differs from Python

sqlite> CREATE TABLE phrase AS SELECT "hello, world" AS s;
sqlite> SELECT substr(s, 4, 2) || substr(s, instr(s, " ")+1, 1) FROM phrase;
low

Strings can be used to represent structured values, but doign so is rarely a good idea

Cartesian Product of Two Tables

• We pair up every row within a table to every row within the other table, such that each table's row is matched 1-to-1 with each other table's row.
• Essentially, if we have the first table with $a$ rows, and another table with $b$ rows, then our final cartesian product table would have $a\times b$ rows.