How to use if exists- if not exists in PL/SQL?

Question

I am trying to convert if exists statement from SQL-Server to PL/SQL but having an error.

I am trying to check if NAME_1 doesn\'t exist in my table_1<

Answer 1

Provided table_2 has no DEFAULT value for third column you can do it much simpler like this one:

DECLARE
    l_count NUMBER;
    l_count_2 NUMBER;
BEGIN
    SELECT COUNT(*) INTO l_count FROM table_1 WHERE NAME='NAME_1';
    IF l_count = 0  THEN
        SELECT COUNT(*) INTO l_count_2 FROM dba_tab_cols  WHERE TABLE_NAME = 'table_1' AND COLUMN_NAME='NAME_2';

        INSERT INTO table_1
        SELECT 'value1', MAX(column), CASE WHEN l_count_2 > 0 THEN 20 ELSE NULL end 
        FROM table_2;

    END IF;       
END;

There is no reason for dynamic SQL.