select a.*,b.table2id,b.column21,b.column23,c.table3id,column31,column32,column33 from table1 a left join table2 b on b.table1id=a.table1id left join table3 c on c.table1id=a.table1id
修改 select a.*,b.table2id,b.column21,b.column22,b.column23,c.table3id,c.column31,c.column32,c.column33 from table1 a left join table2 b on b.table1id=a.table1id left join table3 c on c.table1id=a.table1id
select a.*,b.table2Id,b.table1Id as table2_table1Id,column21,column22,column23, table3Id,c.table1Id as table3_table1Id, table2Id as table3_table2Id,column31,column32,column33 from table1 a left table2 b on a.table1Id=b.table1Id left table3 c on b.table2Id=c.table2Id and b.table1Id=c.table1Id
select a.*,b.table2id,b.column21,b.column22,b.column23,c.table3id,c.column31,c.column32,c.column33
from table1 a
left join table2 b on b.table1id=a.table1id
left join table3 c on c.table1id=a.table1id
table3Id,c.table1Id as table3_table1Id,
table2Id as table3_table2Id,column31,column32,column33
from table1 a left table2 b on a.table1Id=b.table1Id left table3 c
on b.table2Id=c.table2Id and b.table1Id=c.table1Id