SQL · Theory

vs SQL

Theory

265/439

vs SQL

SQL is the language (SELECT, INSERT). MySQL is one database product that speaks SQL. Saying ‘I know SQL’ is not the same as ‘I administered MySQL users and dumps’.

You can know SQL and work in Postgres. You can use MySQL and still write bad SQL. Learn both: language + this engine’s types, LIMIT, backticks, AUTO_INCREMENT.

Trap — using them as synonyms in a strict viva.

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

Exam tip

SQL language, MySQL product. Postgres also speaks SQL.

vs SQL — sample query

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

Short notes

DefSQL = language. MySQL = a server that speaks it.
RuleName both in one sentence.
Trap‘SQL and MySQL are the same’.

SQL · Theory

vs SQL

← All stacks

Theory

265/439

vs SQL

SQL is the language (SELECT, INSERT). MySQL is one database product that speaks SQL. Saying ‘I know SQL’ is not the same as ‘I administered MySQL users and dumps’.

You can know SQL and work in Postgres. You can use MySQL and still write bad SQL. Learn both: language + this engine’s types, LIMIT, backticks, AUTO_INCREMENT.

Trap — using them as synonyms in a strict viva.

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

Exam tip

SQL language, MySQL product. Postgres also speaks SQL.

vs SQL — sample query

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

Short notes

DefSQL = language. MySQL = a server that speaks it.
RuleName both in one sentence.
Trap‘SQL and MySQL are the same’.

vs SQL

vs SQL — sample query

Short notes

Questions

vs SQL

vs SQL — sample query

Short notes

Questions