Msg 244 and Msg 245 come from converting a value to an incompatible data type, often with CAST or ISNULL. Examples of both, and why ISNULL casts to the first type.
Explaining a Database to Non-Programmers (It Won’t Play Your Flash Movie)
Explaining a database to non-programmers is a real skill. Here’s my old flash movie story and the plain comparisons that work in any meeting.
SQL SERVER – Convert Text to Numbers (Integer) – CAST and CONVERT
How to convert text to integer with CAST and CONVERT, whether they fail on alpha-numeric values (yes), and how to pull only the numbers from a string.
SQL SERVER – FIX : Error : msg 8115, Level 16, State 2, Line 2 – Arithmetic overflow error converting expression to data type
Msg 8115, arithmetic overflow error, comes when a value is too big for its column, like 111111 in a TINYINT. Check the value or widen the column definition.
CONCAT_WS: Keep NULL and Empty Strings Separate
CONCAT_WS joins values with a separator, but NULL and empty strings have different effects. These examples keep the original fields beside the combined text and byte length.
LAST_VALUE: Set the Window Frame for the Final Row
LAST_VALUE changes with its window frame. Compare implicit and whole-partition frames, order tied rows and preserve a final NULL.
BIT_COUNT: Count Set Bits Without Changing Integer Width
BIT_COUNT counts active positions in a typed value. Keep integer width visible and distinguish a missing mask from a zero count.