CREATE TABLE search_query {
  keyword VARCHAR (30),
  occurrences INT
}

keyword occurrences
HOW     0
TO      0
CODE    0
THIS    0

CREATE TABLE product_keywords {
  productId INT,
  keyword VARCHAR(30)
}

productId  keyword
12         HOW
12         NOT
12         CODE
13         RANDOM
13         THIS
13         CODE

HOW    1
TO     0
CODE   2
THIS   1

UPDATE destination_table
SET destination_table.occurrences = JN.matches
FROM search_query AS destination_table
INNER JOIN  [where I freeze] AS JN
WHERE ....