想從兩個表，在這裏我需要數列，並加入選擇數據

Question

我有一個表名塊兩個數據表

|ID | Name | 
|1 | B1 | 
|2 | B2 | 

然後，我有另一臺命名爲block_worker

|block_id | Name | No Of Worker| 
|1  | sam| 
|1  | dave| 
|2  | Rob | 

現在我想寫一個查詢，它顯示我從塊表中的數據，並根據block id統計block worker表中的工人數。

的結果會是這樣的

|ID | Name | Worker 
|1 | B1 | 2 | 
|2 | B2 | 1 | 

Answer 1

select b.id, b.name, count(w.name) as Workers 
from block b 
left join block_worker w on w.block_id = b.id 
group by b.id, b.name 

Answer 2

Try Like this 

    SELECT A.ID,A.Name,COUNT(B.block_id) AS Worker FROM block AS A JOIN block_worker AS B 
ON A.ID = B.block_id GROUP BY B.block_id