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How can you combine two tables/views together? For instance one table contains 100 rows and the other one contains 200 rows, have exactly the same fields and you want to show a query with all data (300 rows).

    SELECT column_name FROM table_name1
    SELECT column_name FROM table_name2


  • UNION 内部的 SELECT 语句必须拥有相同数量的列.
  • 列也必须拥有相似的数据类型.
  • 每条 SELECT 语句中的列的顺序必须相同.
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