Does MySQL Lack a Robust Row Generator Like Oracle's CONNECT BY or PostgreSQL's generate_series()?

MySQL Row Generator: Limited Alternatives

Unlike other database systems, MySQL lacks the ability to generate an arbitrary number of rows for a JOIN operation as in Oracle syntax.

This limitation creates challenges when looking for a versatile row generator comparable to Oracle's CONNECT BY clause or PostgreSQL's generate_series() function. However, there are some alternatives to simulate row generation in MySQL:

• Nested SELECT statement:

<code class="language-sql">WITH RECURSIVE Hier(Row) AS (
  SELECT 1 UNION ALL
  SELECT Row + 1 FROM Hier
  WHERE Row < 10
)
SELECT * FROM Hier;</code>

• Use WHILE loop:

<code class="language-sql">DECLARE Row INT DEFAULT 0;

WHILE Row < 10 DO
  -- 在这里插入你的逻辑，例如插入到临时表中
  SET Row = Row + 1;
END WHILE;</code>

These methods simulate row generation by iteratively generating a specified number of rows and storing them in a temporary table. However, they require additional temporary tables and query structures, making them less efficient than dedicated row generators.

Therefore, it is important to understand the limitations of MySQL with respect to row generation and explore alternative ways of achieving similar functionality.

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