SQL · Theory

vs Oracle

Theory

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vs Oracle

Oracle Database is a commercial RDBMS. MySQL is open-source (Oracle the company also owns the MySQL product). SELECT/JOIN ideas transfer. PL/SQL, DUAL, VARCHAR2, NVL are Oracle dialect — use IFNULL/CASE in MySQL.

Trap — saying they are the same. Trap: ‘MySQL has no transactions’ — InnoDB does.

On the example next to this theory: vs Oracle: create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Exam tip

Same relational idea, different product and dialect.

vs Oracle — sample query

-- vs Oracle
CREATE TABLE demo (
  id INTEGER PRIMARY KEY,
  label TEXT NOT NULL,
  qty INTEGER DEFAULT 0
);
INSERT INTO demo (id, label, qty) VALUES
  (1, 'alpha', 2),
  (2, 'beta', 5);
SELECT label, qty FROM demo WHERE qty >= 2 ORDER BY qty DESC;

vs Oracle: create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Short notes

DefOracle = commercial RDBMS. MySQL = open-source RDBMS. Both SQL.
RuleCore SELECT transfers. Dialects differ.
TrapCalling them the same product.

-- vs Oracle CREATE TABLE demo ( id INTEGER PRIMARY KEY, label TEXT NOT NULL, qty INTEGER DEFAULT 0 ); INSERT INTO demo (id, label, qty) VALUES (1, 'alpha', 2), (2, 'beta', 5); SELECT label, qty FROM demo WHERE qty >= 2 ORDER BY qty DESC;

vs Oracle

vs Oracle — sample query

Short notes

Questions

vs Oracle

vs Oracle — sample query

Short notes

Questions