245: Conversion failed when converting the value to data type

What does it mean?

A value could not be converted to the target data type. For example, an implicit/explicit conversion failed because of unsuitable content while converting a string value to int or date.

Why does it happen?

Converting non-numeric text to int/decimal, an invalid date format, implicit type conversion in column comparisons, incompatible types in a WHERE or JOIN condition, or malformed input data.

How to fix it

Use the safe conversion variants: TRY_CAST or TRY_CONVERT (return NULL on failure). Identify bad rows with ISNUMERIC/TRY_CONVERT. Align column types and eliminate implicit conversion. Validate input and use an explicit format for dates (e.g. a CONVERT style).