在SQL中进行行之间的数据转换通常需要使用一些聚合函数和子查询来实现。以下是一些常见的方法:
SELECT
CASE
WHEN column_name = value1 THEN 'new_value1'
WHEN column_name = value2 THEN 'new_value2'
ELSE 'default_value'
END AS new_column
FROM table_name;
SELECT t1.column1, t2.new_column
FROM table1 t1
JOIN (
SELECT column_name,
CASE
WHEN column_name = value1 THEN 'new_value1'
WHEN column_name = value2 THEN 'new_value2'
ELSE 'default_value'
END AS new_column
FROM table2
) t2 ON t1.column1 = t2.column_name;
SELECT
column1, SUM(column2) AS total_column2
FROM table_name
GROUP BY column1;
这些方法可以帮助在SQL中实现行之间的数据转换,具体使用哪种方法取决于需要实现的具体需求和数据结构。