How Can I Efficiently Import CSV Files into SQL Server, Handling Commas, Double Quotes, and Bad Data?

Mastering CSV File Imports into SQL Server: Addressing Key Challenges

This guide addresses common hurdles encountered when importing CSV files into SQL Server using the BULK INSERT command. We'll examine three primary problems and their effective solutions.

Challenge 1: Embedded Commas within Data Fields

CSV data often contains commas within fields (e.g., "John Doe, Jr."), which BULK INSERT interprets as field separators. The solution is to specify an alternative field delimiter, such as "||", within the BULK INSERT statement:

<code class="language-sql">BULK INSERT SchoolsTemp
FROM 'C:\CSVData\Schools.csv'
WITH
(
    FIELDTERMINATOR = '||'
)</code>

Challenge 2: Handling Double Quotes from Excel Exports

Excel-exported CSV files frequently use double quotes to encapsulate fields containing commas. BULK INSERT doesn't inherently support this. A post-import UPDATE statement efficiently removes these quotes:

<code class="language-sql">UPDATE table
SET column_with_quotes = REPLACE(column_with_quotes, '"', '')</code>

Challenge 3: Identifying and Managing Invalid Data

To pinpoint rows with problematic data that failed to import, utilize the ERRORFILE option. This directs BULK INSERT to write details of these rows to a separate error file:

<code class="language-sql">BULK INSERT SchoolsTemp
FROM 'C:\CSVData\Schools.csv'
WITH
(
    ERRORFILE = 'C:\CSVData\SchoolsErrorRows.csv'
)</code>

By implementing these techniques, you can streamline your CSV import process into SQL Server and effectively manage potential data inconsistencies.

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