Difference Between CAST and CONVERT

CAST vs CONVERT

Data conversion is one of the most frequent activities in a database. This is the reason why there are available functions for this particular action.

Both CAST and CONVERT are functions used to convert one data type to another data type. It is mainly used in the Microsoft SQL program, and both are often used interchangeably. The Microsoft SQL server provides both functions to enable a user to change a data type and convert it to another if needed. Both CAST and CONVERT provide a way to write program procedures or queries. In many instances, both CAST and CONVERT are used in combination and with each other to achieve certain effects in the data. Without using CAST or CONVERT functions, implicit conversions occur.

The first difference between CAST and CONVERT is CAST is an ANSI standard while CONVERT is a specific function in the SQL server. There are also differences when it comes to what a particular function can and cannot do.

For example, a CONVERT function can be used for formatting purposes especially for date/time, data type, and money/data type. Meanwhile, CAST is used to remove or reduce format while still converting. Also, CONVERT can stimulate set date format options while CAST cannot do this function.

CAST is also the more portable function of the two. It means that the CAST function can be used by many databases. CAST is also less powerful and less flexible than CONVERT. On the other hand, CONVERT allows more flexibility and is the preferred function to use for data, time values, traditional numbers, and money signifiers. CONVERT is also useful in formatting the data’s format.

CAST functions also restore the decimals and numerical values to integers while converting. It also can be used to truncate the decimal portion or value of an integer.

There are also differences in the CAST and CONVERT syntax. The syntax of CAST is very simple. It includes the value to convert and the type of resulting data type. It has “AS” as keywords to separate the data type from the value. There is an option to express the length which is the integer that specifies the length of the target data type.

On the other hand, the CONVERT syntax mentions the resulting data type first along with the optional length. There is another expression and another optional parameter called style in the CONVERT function. Style allows formatting the data type and specifies how the CONVERT function should translate or format the data type. The CONVERT function doesn’t need a keyword to separate the values and the data type.

Summary:

1.CAST and CONVERT are two SQL functions used by programmers to convert one data type to another.
2.The CAST function is ANSI standard and is compatible to use in other databases while the CONVERT function is a specific function of the SQL server.
3.Since the CAST function is compatible with other databases, it is also described as portable though it has fewer features compared to the CONVERT function. The CONVERT function, meanwhile, can do some things that the CAST function cannot.
4.The CAST function is used to convert a data type without a specific format. The CONVERT function does converting and formatting data types at the same time.
5.In terms of syntax, both functions have the optional parameter of length. In the CONVERT function, there is an additional parameter called style which specifies the format of the data type after conversion.
6.The CAST function is often used to preserve decimal values and places while converting them into integers. The function can also truncate the decimal value if needed. The CONVERT function cannot perform this task.

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