How to Select the nth Row from a Database Table Using a Database-Agnostic Approach?

Retrieving the nth Row from a Database Table: A Cross-Database Solution

Extracting the nth row from a database table is a common task in data manipulation and analysis. While each database system has its own methods, using a database-agnostic approach offers greater flexibility and portability.

The Standard Approach: Window Functions

The SQL standard incorporates window functions, enabling calculations across ordered table rows. The ROW_NUMBER() function assigns a unique number to each row, allowing you to filter for the desired nth row.

<code class="language-sql">SELECT *
FROM (
  SELECT
    ROW_NUMBER() OVER (ORDER BY <column_name>) AS rownumber,
    <other_columns>
  FROM <table_name>
) AS ranked_rows
WHERE rownumber = <n>;</code>

Database-Specific Alternatives

If your database doesn't support window functions, consider these database-specific options:

• MySQL, PostgreSQL: Utilize the LIMIT and OFFSET clauses:

<code class="language-sql">SELECT *
FROM <table_name>
LIMIT 1 OFFSET <n>;</code>

• SQL Server: Employ the ROW_NUMBER() function within a common table expression (CTE):

<code class="language-sql">WITH NumberedRows AS (
  SELECT ROW_NUMBER() OVER (ORDER BY <column_name>) AS RowNumber, <other_columns>
  FROM <table_name>
)
SELECT *
FROM NumberedRows
WHERE RowNumber = <n>;</code>

Further Reading

• Database Window Functions Across Various Systems
• Standard SQL Window Function Documentation

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