mysql同時update多行

1. 當我們只更新一個字段時的語法如下:

   UPDATE mytable
       SET myfield = CASE other_field
           WHEN 1 THEN 'value'
           WHEN 2 THEN 'value'
           WHEN 3 THEN 'value'
       END
   WHERE id IN (1,2,3)

2. 當我們只更新多個字段時的語法如下:

   UPDATE categories
       SET display_order = CASE id
           WHEN 1 THEN 3
           WHEN 2 THEN 4
           WHEN 3 THEN 5
       END,
       title = CASE id
           WHEN 1 THEN 'New Title 1'
           WHEN 2 THEN 'New Title 2'
           WHEN 3 THEN 'New Title 3'
       END
   WHERE id IN (1,2,3)