根据同一张表的其他值插入值

Question

lets assume I have a table like this:

Column A	Column B
120
90
60
150

Now I want to fill the empty column B with string values somehow like this:

if column A > 100: insert "high number" else: insert "low number"

So that: 120 -> high number, 90 -> low number, etc...

How would I do that in Oracle SQL?

Thanks in advance:)

Answer 1

You can use an UPDATE statement with a CASE expression:

UPDATE table_name
SET column_b = CASE
               WHEN column_a > 100
               THEN 'high number'
               ELSE 'low number'
               END;

However, it would be better, to make column_b a virtual column:

CREATE TABLE table_name (
  column_a NUMBER,
  column_b VARCHAR2(11) 
           GENERATED ALWAYS AS (
             CASE 
             WHEN column_a > 100
             THEN 'high number'
             ELSE 'low number'
             END
           )
);

Then if the column_a value changes the column_b value will stay in sync with it.

fiddle