SQL CONVERT Function Guide

In SQL, the CONVERT() function is used to change one data type to another. It can be used to convert strings to numbers, dates, or other data types, as well as converting numbers, dates, or other data types to strings.

The syntax for the CONVERT() function is as follows:

CONVERT(data_type, expression, [style])

In this case, data_type is the target data type to be converted, expression is the expression to be converted, and style is an optional parameter used to specify the conversion style.

Below are some common usage examples:

1. Convert the string to an integer.

SELECT CONVERT(INT, '123') AS ConvertedValue;

The result is:

ConvertedValue
--------------
123

1. Convert the date string to a date type.

SELECT CONVERT(DATE, '2022-01-01') AS ConvertedDate;

The result is:

ConvertedDate
-------------
2022-01-01

1. Convert the numbers to strings.

SELECT CONVERT(VARCHAR(10), 123) AS ConvertedString;

The result is:

ConvertedString
---------------
123

These are just a few common usage examples of the CONVERT() function, which can also be used for other types of conversions such as converting strings to times, dates to strings, and so on. When using it, you can adjust the data type and style parameters according to your needs.