CAST DECIMAL to INT

You could try the FLOOR function like this:

SELECT FLOOR(columnName), moreColumns, etc 
FROM myTable 
WHERE ... 

You could also try the FORMAT function, provided you know the decimal places can be omitted:

SELECT FORMAT(columnName,0), moreColumns, etc 
FROM myTable 
WHERE ... 

You could combine the two functions

SELECT FORMAT(FLOOR(columnName),0), moreColumns, etc 
FROM myTable 
WHERE ... 

A more optimized way in mysql for this purpose*:

SELECT columnName DIV 1 AS columnName, moreColumns, etc
FROM myTable
WHERE ...

Using DIV 1 is a huge speed improvement over FLOOR, not to mention string based functions like FORMAT

(graphic from Roland Bouman's blog)

mysql> SELECT BENCHMARK(10000000,1234567 DIV 7) ;
+-----------------------------------+
| BENCHMARK(10000000,1234567 DIV 7) |
+-----------------------------------+
|                                 0 |
+-----------------------------------+
1 row in set (0.83 sec)

mysql> SELECT BENCHMARK(10000000,1234567 / 7) ;
+---------------------------------+
| BENCHMARK(10000000,1234567 / 7) |
+---------------------------------+
|                               0 |
+---------------------------------+
1 row in set (7.26 sec)

mysql> SELECT BENCHMARK(10000000,FLOOR(1234567 / 7)) ;
+----------------------------------------+
| BENCHMARK(10000000,FLOOR(1234567 / 7)) |
+----------------------------------------+
|                                      0 |
+----------------------------------------+
1 row in set (8.80 sec)

(*) NOTE: As pointed by Grbts, be aware of the behaviour of DIV 1 when used with non unsigned/positive values.

From the article you linked to:

The type can be one of the following values:

BINARY[(N)]

CHAR[(N)]

DATE

DATETIME

DECIMAL[(M[,D])]

SIGNED [INTEGER]

TIME

UNSIGNED [INTEGER]

Try SIGNED instead of INT

The CAST() function does not support the "official" data type "INT" in MySQL, it's not in the list of supported types. With MySQL, "SIGNED" (or "UNSIGNED") could be used instead:

CAST(columnName AS SIGNED)

However, this seems to be MySQL-specific (not standardized), so it may not work with other databases. At least this document (Second Informal Review Draft) ISO/IEC 9075:1992, Database does not list "SIGNED"/"UNSIGNED" in section 4.4 Numbers.

But DECIMAL is both standardized and supported by MySQL, so the following should work for MySQL (tested) and other databases:

CAST(columnName AS DECIMAL(0))

According to the MySQL docs:

If the scale is 0, DECIMAL values contain no decimal point or fractional part.

use this

mysql> SELECT TRUNCATE(223.69, 0);
        > 223

Here's a link