# Dynamic parameters

You can prepare statements that are allowed to have parameters for which the value is not specified when the statement is prepared using PreparedStatement methods in the JDBC API. These parameters are called dynamic parameters and are represented by a question mark (`?`).

The JDBC API documentation refers to dynamic parameters as IN, INOUT, or OUT parameters. In SQL, they are always IN parameters.

You must specify values for dynamic parameters before executing the statement. The values specified must match the types expected.

- Dynamic parameters example
- Where dynamic parameters are allowed
  You can use dynamic parameters anywhere in an expression where their data type can be easily deduced.

Parent topic: SQL expressions
Related reference
selectExpression
tableExpression
NEXT VALUE FOR expression
VALUES expression
Expression precedence
Boolean expressions
CASE expression