CAST function in PostgreSQL

[amna]

how to use cast function in postgresql?

 

[msiqbal]

how to use cast function in postgresql?

CAST function:​

In PostgreSQL, the CAST function is used to convert a value of one data type to another data type. The basic syntax of the CAST function is as follows:

SQL

CAST (expression AS target_type)

Here, expression is the value that needs to be converted, and target_type is the data type to which the value needs to be converted. The CAST function can be used in a SELECT statement, INSERT statement, UPDATE statement, or any other SQL statement that requires data type conversion.

Let's see some examples of using the CAST function in PostgreSQL:

Example 1: Convert a string to an integer​

sql

SELECT CAST('123' AS INTEGER);

Output:​

markdown

int4
-----
123

In this example, we are converting the string value '123' to an integer using the CAST function. The output shows that the value has been converted to an integer.

Example 2: Convert a decimal to an integer​

sql

SELECT CAST(12.34 AS INTEGER);

Output:​

markdown

int4
-----
12

In this example, we are converting the decimal value 12.34 to an integer using the CAST function. The output shows that the value has been converted to an integer by truncating the decimal portion.

Example 3: Convert a timestamp to a date​

sql

SELECT CAST('2022-03-14 12:34:56' AS DATE);

Output:​

markdown

date
------------
2022-03-14

In this example, we are converting a timestamp value '2022-03-14 12:34:56' to a date using the CAST function. The output shows that the value has been converted to a date by discarding the time portion.

That's how you can use the CAST function in PostgreSQL to convert values from one data type to another