MySQL Insert/Update or both

mysql_insert_update_options.sql

-- In the below example there is a unique key for scope, scope_id, and path
-- We can choose to only insert a record if it doesn't exist, only update
-- a record that doesn't exist, or accomodate both to ensure that a record
-- exists afterwards, either inserted, or updated for the matching key.


-- Only insert a record if it does not already exist
INSERT INTO core_config_data (scope, scope_id, path, value)
SELECT * FROM (SELECT 'default', '0', 'catalog/search/engine', 'enterprise_search/engine') AS to_insert
WHERE NOT EXISTS (
   SELECT path FROM core_config_data WHERE scope = 'default' and scope_id = 'default' and path = 'catalog/search/engine'
) LIMIT 1;
-- or
INSERT IGNORE INTO core_config_data
    (scope, scope_id, path, value)
VALUES
    ('default', '0', 'catalog/search/engine', 'enterprise_search/engine');


-- Only update an existing record otherwise do nothing
UPDATE core_config_data SET value = 'enterprise_search/engine' WHERE path = 'catalog/search/engine';


-- Either Insert new record or update existing record if duplicate key exists
-- This works for duplicate unique or primary keys
-- This seems similar to a term I've heard of called "indate" where an insert is 
-- tried first, and if that can not complete an update is performed. That being
-- a bit different than "upsert" an attempt to update, and if failed, insert, which 
-- seems similar but may not be the same. I don't believe there is anything in 
-- MySQL directly referencing upsert/indate support, but this affectively accomodate
-- the same kind of need provided it can be triggered around a unique key.
INSERT INTO core_config_data (scope, scope_id, path, value)
VALUES ('default', '0', 'catalog/search/engine', 'enterprise_search/engine')
ON DUPLICATE KEY UPDATE
  value = '1';
-- or
SET @scope = 'default',
    @scope_id = '0',
    @path = 'catalog/search/engine',
    @value = 'enterprise_search/engine';
INSERT INTO core_config_data 
    (scope, scope_id, path, value)
VALUES 
    (@scope, @scope_id, @path, @value)
ON DUPLICATE KEY UPDATE
    value = @value;