打開更新/加入到查詢

Question

我

Update2 `Table1` AS T1 Inner Join `Table2` As T2 
On T2.`Name` = T1.Name 
Set T1.`ParentID` = T2.`ID` 

我想先檢查一下，讓大腦凍結長週末之後，幫助表示讚賞。

我基本上要首先檢查

Select FieldA, concat(FieldC,', ',FieldD) `Table1` AS T1 Inner Join `Table2` As T2 
on T2.`Name` = T1.Name 
Set T1.`ParentID` = T2.`ID` 

，以確保我得到正確的結果。

Answer 1

的等效SELECT可以是：

SELECT T1.`ParentID` = T2.`ID` 
FROM `Table1` AS T1 Inner Join `Table2` AS T2 
    ON T2.`Name` = T1.Name 

pt-query-digest是轉化更新導入的SELECT所以它可以運行解釋工具的一個例子。