Converting Integers to Text in PostgreSQL: A Guide to the CAST Operator

In PostgreSQL, converting integers to text is a common operation that requires careful planning. The CAST operator is used to type cast from one data type to another, ensuring that the data can be converted to the target data type or qualifies to be of the target data type too. In this article, we will explore how to use the CAST operator in PostgreSQL and provide practical examples.

Why Do We Need Casting?

Let's consider a simple scenario where we want to add two numbers stored in two columns of a row/record in a table. Suppose one column stores numbers as integers, while the other column stores them as strings (varchar). To perform the addition, we need to cast these numbers to integer once.

Using the CAST Operator

The syntax for using the CAST operator is: `CAST (expression AS target_type)`. The expression can be a constant or a table column or any expression that finally resolves to a value. The target_type is the final data type to which you want to convert the above expression.

For example, if we want to convert an integer datatype to string datatype, we can use: `SELECT CAST(97 AS varchar)`. This will return the number 97 as a string.

Converting Integer to String

Suppose we have a column that stores numbers/integers, but the data type has been set as varchar by the database administrator. To convert this integer to a string, we can use: `SELECT CAST(column_name AS varchar)`. This will return the number from the column as a varchar (or string).

Example Scenario

Suppose we have two columns, 'num1' and 'num2', that store numbers as integers. We want to add these numbers and return the result as a string. We can use the following query: `SELECT CAST(num1 AS text) + CAST(num2 AS text) FROM table_name`.

In this article, we have explored how to convert integers to text in PostgreSQL using the CAST operator. The CAST operator is a powerful tool that allows us to type cast from one data type to another. By understanding its syntax and usage, we can perform various cast operations in PostgreSQL for converting one data type to another.

Postgresql cast integer to text