Listed in table a station and cause two field data, I think in the decision table in table b a station and the cause of both field data exist, there is no wrote in table b, thank you

CodePudding user response:

Column turned after comparison table b, there is no insert

CodePudding user response:

 
Insert into table b (station, cause) 
The select a.s tation, a.c ause 
A. the from list a 
Left the join table b b 
On a.s tation=b.s tation 
And a.c ause=biggest ause 
Where b.s tation is null