Chapter 10. Type Conversion

SQL statements can, intentionally or not, require the mixing of different data types in the same expression.PostgreSQL has extensive facilities for evaluating mixed-type expressions.

In many cases a user does not need to understand the details of the type conversion mechanism. However, implicit conversions done byPostgreSQL can affect the results of a query. When necessary, these results can be tailored by usingexplicit type conversion.

This chapter introduces thePostgreSQL type conversion mechanisms and conventions. Refer to the relevant sections inChapter 8 andChapter 9 for more information on specific data types and allowed functions and operators.