Convert(int,sys.fn_sqlvarbasetostr(hashbytes('md5','1455985476')))

: Creating a non-obvious integer ID from a sensitive string.

: This generates a 128-bit MD5 hash of the input string, returned as a varbinary value.

: This attempts to cast that hex string into a 4-byte integer. Because the hash is much larger than an integer, SQL Server typically truncates the value, often resulting in an arithmetic overflow or returning a signed integer based on the last 4 bytes of the hash. The Result : Creating a non-obvious integer ID from a sensitive string

: Distributing data rows into different "buckets" or shards by hashing a unique ID.

The SQL expression you provided is a specific method used in SQL Server to generate a or "sharding key" from a string value (in this case, the string '1455985476' ). Breaking Down the Code Because the hash is much larger than an

: This internal (undocumented) function converts the binary hash into its string representation (e.g., '0x792106533f84b730c64951a1ea702c78' ).

For the specific input '1455985476' , the MD5 hash is 792106533f84b730c64951a1ea702c78 . Converting the relevant portion of this hex value to a signed 32-bit integer results in: Common Use Cases Breaking Down the Code : This internal (undocumented)

: Using sys.fn_sqlvarbasetostr is generally discouraged in production code because it is an undocumented internal function. A more standard approach in T-SQL is CONVERT(INT, HashBytes('MD5', '...'), 2) or directly casting the binary to an integer.