how to insert into one column at a time sql code example

Example 1: how to add records to sql table

INSERT INTO Customer (FirstName, LastName, City, Country, Phone)
VALUES ('Craig', 'Smith', 'New York', 'USA', 1-01-993 2800)

Example 2: insert to first table if field A equals field B from a second table using sql

UPDATE Table_1 SET Field_X = (SELECT Field_Y FROM Table_2 WHERE Table_1.Field_A=Table_2.Field_B LIMIT 1)