Insert into table values from another table only if they meet certain criteria

Question

I'm trying to create the following pseudocode in MySQL. I have the following tables:

• specials
• product_filter

The product_filter table only has two columns, product_id and filter_id

I'd like to come up with a SQL that:

1. Reads all product_ids from the specials table and puts them in the product_filter table
2. When reading the product id from the specials table, it needs to look at the price column too
3. If the price is under $100, the filter id would be 1
4. If the price is between $100 and $500, the filter id would be 2
5. If the price is between $500 and $1000, the filter id would be 3

Here is what I have so far:

INSERT INTO product_filter (product_id,filter_id)
SELECT product_id, 
FROM specials;

Any help is appreciated.

Answer 1

Try this, using a CASE to determine what the filter_id is (this will set anything that doesn't have a price in those boundaries equal to 0):

INSERT INTO product_filter (product_id,filter_id)
SELECT product_id,
    (CASE WHEN price < 100 then 1
    WHEN price >= 100 AND price < 500 then 2
    WHEN price >= 500 AND price < 1000 then 3
    ELSE 0 END) AS filter_id
FROM specials;

Here's a working SQLFiddle .

Answer 2

try this query (you didn't specify for values higher than 1000 so it'll make filter_id 4 if values are greater than 1000).

INSERT INTO product_filter (product_id,filter_id)
SELECT product_id,
       CASE WHEN price < 100 THEN 1
            WHEN price BETWEEN 100 AND 500 THEN 2
            WHEN price BETWEEN 500 AND 1000 THEN 3
            ELSE 4
       END as filter_id
FROM specials;

Answer 3

Use something like this:

INSERT INTO product_filter (product_id,filter_id)
SELECT
  product_id, 
  (CASE
       WHEN price < 100 THEN 1 
       WHEN price BETWEEN 100 AND 500 THEN 2
       WHEN price BETWEEN 500 AND 1000 THEN 3
   END) as filter_id
 FROM specials;

Answer 4

Try this:

You also need minor change in between clause range values as shown below:

INSERT INTO product_filter (product_id,filter_id)
SELECT product_id, 
       case when price < 100 then 1 -- price under $100, the filter id be 1
            -- price between $100 and $500, the filter id be 2
            when price between 101 and 500 then 2
            -- price between $500 and $1000, the filter id be 3
            when price between 501 and 1000 then 3
            -- else ? -- fill this as you need
FROM specials;