DML : Insert , update , Delete , merge

INSERT

Adds new rows to a table, e.g. INSERT INTO employees (id, name) VALUES (101, 'Asha');

UPDATE

Modifies existing rows, e.g. UPDATE employees SET name = 'Asha K' WHERE id = 101; — always paired with a WHERE clause to avoid updating every row unintentionally.

DELETE

Removes rows, e.g. DELETE FROM employees WHERE id = 101; — like UPDATE, omitting the WHERE clause deletes every row in the table.

MERGE

Combines insert and update logic into one statement, commonly used to synchronize a target table with a source: inserting rows that don't exist yet and updating rows that do, based on a matching condition.