if exists(select * from a where id=33) select * from a else begin if exists(select * from b where id=33) select * from b else begin if exists(select * from c where id=33) select * from c end end 你试试吧!
select a.*,b.*,c.* from a,b,c wher a.id=33 or b.id=33 or c.id=33 這樣就可以查出id=33的記錄的字段了
输出列如果相同(数据类型兼容)的话,那就用 select column1,...columnn from tablename where id=xxxx union select col1,......coln from tablename2 where id=xxxx .......如果某表列数不足那就按,数据类型进行一一对应并输出null补充不足列作为输出
if exists(select 1 from a where id = 33) select * from a where id = 33 else if exists(select 1 from b where id = 33) select * from b where id = 33 else if exists(select 1 from c where id = 33) select * from c where id = 33
select * from a
else
begin
if exists(select * from b where id=33)
select * from b
else
begin
if exists(select * from c where id=33)
select * from c
end
end
你试试吧!
這樣就可以查出id=33的記錄的字段了
select column1,...columnn from tablename where id=xxxx
union
select col1,......coln from tablename2 where id=xxxx
.......如果某表列数不足那就按,数据类型进行一一对应并输出null补充不足列作为输出
select * from a where id = 33
else if exists(select 1 from b where id = 33)
select * from b where id = 33
else if exists(select 1 from c where id = 33)
select * from c where id = 33