@varname, :varname, ?varname
(e.g.) SELECT * FROM TABLE WHERE COL1=@varname

(Specifying a fixed variable) :setvar <varname> "value"
(Specifying a dynamic variable) :setvar <varname>
(Using a variable) $(varname)
e.g.
:setvar FixedVar "%e%"
:setvar DynamicVar
SELECT * FROM [Categories] WHERE [CategoryName] LIKE '$(FixedVar)' AND [CategoryID]=$(DynamicVar)

You can separate multiple SQL statements by the word "GO", the symbol "/" or "Custom delimiter".
e.g.
CREATE TABLE a1 (cola1 int NOT NULL PRIMARY KEY)
GO
DROP TABLE a1
GO

e.g.
CREATE TABLE a1 (cola1 int NOT NULL PRIMARY KEY)
/
DROP TABLE a1
/

e.g.
DELIMITER $$
CREATE TABLE a1 (cola1 int NOT NULL PRIMARY KEY)
$$
DROP TABLE a1
$$

e.g.
SET TERM ^
CREATE TABLE a1 (cola1 int NOT NULL PRIMARY KEY)
^
DROP TABLE a1
^