我在本地Postgres数据库中有3个表:
I have 3 tables in my local Postgres database:
[myschema].[animals] -------------------- animal_id animal_attrib_type_id (foreign key to [myschema].[animal_attrib_types]) animal_attrib_value_id (foreign key to [myschema].[animal_attrib_values]) [myschema].[animal_attrib_types] -------------------------------- animal_attrib_type_id animal_attrib_type_name [myschema].[animal_attrib_values] -------------------------------- animal_attrib_value_id animal_attrib_value_name在运行时,我会知道 animal_id 。我需要运行SQL来更新与此项目关联的 animal_attribute_value_name ,类似这样:
At runtime I will know the animal_id. I need to run SQL to update the animal_attribute_value_name associated with this item, so something like:
UPDATE animal_attribute_values aav SET aav.animal_attribute_value_name = 'Some new value' WHERE # Somehow join from the provided animal_id???我可能必须做某种嵌套的 SELECT $ c $ WHERE 子句中的c>或 INNER JOIN ,但不确定如何执行此操作。
I may have to do some kind of nested SELECT or INNER JOIN inside the WHERE clause, but not sure how to do this. Thanks in advance!
编辑:
假设我有一个动物记录,其值如下:
Let's say I have an animal record with the following values:
[myschema].[animals] -------------------- animal_id = 458 animal_attrib_type_id = 38 animal_attrib_value_id = 23对应的 animal_attrib_value (id = 23)具有以下值:
And the corresponding animal_attrib_value (with id = 23) has the following values:
[myschema].[animal_attrib_values] -------------------------------- animal_attrib_value_id = 23 animal_attrib_value_name = 'I am some value that needs to be changed.'在运行时,我只有 animal_id (458)。我需要查找相应的 animal_attrib_value (23)并将其 animal_attrib_value_name 更改为'Some新值 ,都在单个UPDATE语句中。
At runtime, I only have the animal_id (458). I need to look up the corresponding animal_attrib_value (23) and change its animal_attrib_value_name to 'Some new value', all inside of a single UPDATE statement.
推荐答案UPDATE animal_attribute_values aav SET animal_attribute_value_name = 'Some new value' FROM animals aa WHERE aa.animal_id = 458 AND aa.animal_attrib_value_id = aav.animal_attrib_value_id ;
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Postgres使用2个表之间的内部联接进行更新吗?
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