Terminology

Operators

Operators are used to compare values. The following table from wikipedia shows the SQL operators.

SQL Operators
Operator	Description	Example
`=`	Equal to	`value = 'MyString'`
`<>`/`!=`	Not equal	`value != 'MyString'`
`>`	Greater than	`value > 4`
`<`	Less than	`value < 4`
>=	Greater than or equal to	`value >= 4`
⇐	Less than or equal to	`value ⇐ 4`
[`NOT`] `BETWEEN`	Between an inclusive range. Or not between an inclusive range if `NOT BETWEEN`.	`value BETWEEN 1 AND 10` or `value NOT BETWEEN 1 AND 10`
[`NOT`] `IN`	Equal to one of many possible values. Or not equal to one of many possible values.	`value IN (1, 2, 3)` or `value NOT IN (1, 2, 3)`
`IS` [`NOT`] `NULL`	Compare to `NULL`.	`value IS NULL` or `value IS NOT NULL`
`IS` [`NOT`] `TRUE`/`FALSE`	Compare to `TRUE` or `FALSE`	`value IS TRUE` or `value IS FALSE` or `value IS NOT TRUE` or `value IS NOT FALSE`
`IS NOT DISTINCT FROM`	Is equal to value or both are `NULL`	`value IS NOT DISTINCT FROM other_value`
`AS`	Used to change column name when viewing results	`SELECT abs_val AS 'Absolute value' FROM results;`

Predicates

Predicates are conditions that are evaluated into true or false. For example, the furry = TRUE and has_claws = FALSE portions of the following query evaluates to true.

SELECT * FROM pets WHERE furry = TRUE OR has_claws = FALSE;

Clauses

WHERE, ORDER BY, GROUP BY, HAVING, FROM, TOP/LIMIT, OFFSET

Identifiers

Identifiers are names of database objects, like tables, columns, etc.

Statements

Statements are text sent to a database engine. Typically, statements begin with one of the following keywords, and end in a semi-colon.

SELECT, SELECT DISTINCT, SELECT INTO, INSERT INTO, UPDATE, DELETE

Queries

A query is any statement that returns rows. That means, typically, statements that start with the the following keywords.

SELECT, SELECT DISTINCT