docs: add schema inference note for read_csv, read_parquet, read_avro, and COPY FROM (FIR-50448) (#1102)

Author: devin-ai-integration[bot]

docs-mdx/reference-sql/commands/data-management/copy-from.mdx

@@ -255,6 +255,8 @@ You can use the automatic schema discovery feature in `COPY FROM` to handle even
 * **Parquet files** - Firebolt automatically reads metadata in Parquet files to create corresponding target tables.
 * **CSV files** - Firebolt infers column types based on the data content itself, which can streamline the initial data loading process significantly. Use `WITH HEADER=TRUE` if your CSV file contains column names in the first line.
 
+When loading multiple files, the schema is inferred from the most recently modified file.
+
 Automatic schema discovery operates on a "best effort" basis, and attempts to balance accuracy with practical usability, but it may not always be error-free.
 
 The following query reads `levels.csv`, a sample dataset from the fictional “Ultra Fast Gaming Inc.” company. The example implicitly uses automatic schema creation with `AUTO_CREATE=TRUE`, which defaults to `TRUE`, and also triggers automatic table creation:

docs-mdx/reference-sql/functions-reference/table-valued/read_avro.mdx

@@ -53,6 +53,8 @@ READ_AVRO (
 
 The result is a table with data from the Avro files. Columns are read and parsed using their inferred data types based on the Avro schema. All data types are inferred as nullable.
 
+When reading multiple files, the schema is inferred from the most recently modified file.
+
 ## Avro Data Type Mapping
 
 `READ_AVRO` supports all Avro data types with the following mappings:
@@ -224,4 +226,4 @@ The pattern will recursively match files in all subdirectories. For example:
 ```sql
 SELECT * FROM READ_AVRO('s3://firebolt-publishing-public/help_center_assets/firebolt_sample_avro/*.avro')
 ```
-will read all Avro files in the `firebolt_sample_avro` directory and all of its subdirectories. 
+will read all Avro files in the `firebolt_sample_avro` directory and all of its subdirectories. 

docs-mdx/reference-sql/functions-reference/table-valued/read_csv.mdx

@@ -72,6 +72,8 @@ READ_CSV (
 
 The result is a table with the data from the CSV file. Each cell is read as a `TEXT`.
 
+When reading multiple files, the schema is inferred from the most recently modified file.
+
 ## Examples
 
 ### Using LOCATION object

docs-mdx/reference-sql/functions-reference/table-valued/read_parquet.mdx

@@ -58,6 +58,8 @@ READ_PARQUET (
 
 The result is a table with data from the Parquet files. Columns are read and parsed using their inferred data types.
 
+When reading multiple files, the schema is inferred from the most recently modified file.
+
 ## Best practice
 
 Firebolt recommends using a `LOCATION` object to store credentials for authentication.