mysql - Go:sql RowsAffected with ON DUPLICATE KEY UPDATE

Question

我很难找到一些合适的文档来描述 RowsAffected 值的语义，除此之外:

RowsAffected returns the number of rows affected by an update, insert, or delete. Not every database or database driver may support this.

我正在使用带有 ON DUPLICATE KEY UPDATE 的查询，更新后 RowsAffected 的值为 2。是因为删除和插入减少到执行吗？

服务器是 MySql 服务器 Ver 8.0.12 for osx10.13 on x86_64

Answer 1

mysql_affected_rows() 相当于 SQL 函数 ROW_COUNT() .

对于 INSERT .. ON DUPLICATE KEY UPDATE 文档指出:

For INSERT ... ON DUPLICATE KEY UPDATE statements, the affected-rows value per row is 1 if the row is inserted as a new row, 2 if an existing row is updated, and 0 if an existing row is set to its current values. If you specify the CLIENT_FOUND_ROWS flag, the affected-rows value is 1 (not 0) if an existing row is set to its current values.