14. Data Modification Reference

INSERT, UPDATE, DELETE and MERGE query structure.

INSERT

Return: Value

Add new rows to tables.

Syntax signature:INSERT INTO t (c1, c2) VALUES (v1, v2);

Code snippet:

python

INSERT INTO users (id, name) VALUES (1, 'Alice');

Expected Output:1 row added.

Remember: Always ensure correct syntax formatting when calling INSERT.

UPDATE

Return: Value

Modify existing values in table.

Syntax signature:UPDATE t SET c1 = v1 WHERE condition;

Code snippet:

python

UPDATE users SET status = 'Active' WHERE id = 1;

Expected Output:1 row updated.

Remember: Always ensure correct syntax formatting when calling UPDATE.

DELETE

Return: Value

Delete rows matching query criteria.

Syntax signature:DELETE FROM t WHERE condition;

Code snippet:

python

DELETE FROM users WHERE status = 'Suspended';

Expected Output:Matching rows deleted.

Remember: Always ensure correct syntax formatting when calling DELETE.

MERGE

Return: Value

Perform unified upsert statements.

Syntax signature:

MERGE INTO target USING source ON keys
WHEN MATCHED THEN UPDATE ...
WHEN NOT MATCHED THEN INSERT ...

Code snippet:

python

MERGE INTO target t USING source s ON t.id = s.id
WHEN MATCHED THEN UPDATE SET t.val = s.val
WHEN NOT MATCHED THEN INSERT (id, val) VALUES (s.id, s.val);

Expected Output:Synced target table.

Remember: Always ensure correct syntax formatting when calling MERGE.

Previous Topic13. Set Operators Next Topic15. Views & Indexes