在SQL中使用SELECT COUNT查詢進行LIMIT

Question

我想用另一個表的行數來限制INSERT，如下所示：

INSERT INTO pacte (alianca_en_pacte, tipus)
SELECT id_alianca_en_pacte1 ,tipus_pacte1
FROM c_alianca
LIMIT 0, SELECT COUNT(tipus_pacte1) FROM c_alianca WHERE tipus_pacte1 IS NOT NULL

以下查詢：

SELECT COUNT(tipus_pacte1) FROM c_alianca WHERE tipus_pacte1 IS NOT NULL

返回4

運行腳本時，出現以下錯誤：

您的SQL語法有誤； 檢查與您的MySQL服務器版本相對應的手冊以獲取正確的語法，以在第4行的“ SELECT * FROM c_alianca”附近使用

Answer 1

為什么不只是查詢您的條件並插入這樣的條件？

INSERT INTO pacte (alianca_en_pacte, tipus)
SELECT id_alianca_en_pacte1 ,tipus_pacte1
FROM c_alianca
WHERE tipus_pacte1 IS NOT NULL

Answer 2

MySQL當前不支持將子查詢作為LIMIT的參數。 您將需要在兩個查詢中使用用戶變量：

SET @limit = (
    SELECT COUNT(tipus_pacte1) FROM c_alianca WHERE tipus_pacte1 IS NOT NULL
);

INSERT INTO pacte (alianca_en_pacte, tipus)
    SELECT id_alianca_en_pacte1 ,tipus_pacte1
    FROM c_alianca
    LIMIT 0, @limit;

但是正如Nesim Razon所建議的那樣 ，在您的示例中可以避免完全使用LIMIT ：

INSERT INTO pacte (alianca_en_pacte, tipus)
    SELECT id_alianca_en_pacte1 ,tipus_pacte1
    FROM c_alianca
    WHERE tipus_pacte1 IS NOT NULL;

Answer 3

這是你所追求的

INSERT INTO pacte (alianca_en_pacte, tipus)
SELECT id_alianca_en_pacte1, tipus_pacte1, 
    ( SELECT COUNT(tipus_pacte1) FROM c_alianca WHERE tipus_pacte1 IS NOT NULL ) AS tipus 
FROM c_alianca LIMIT 0

Answer 4

below is the code for Limitation on ID....It is the example for you
Declare @Counter int 
Set @Counter=(SELECT Count(Student_ID) as 'StudentCount' FROM CourseSemOne 
where Student_ID=1 Having Count(Student_ID) < 6 and Count(Student_ID) > 0)
if(@Counter <6)
print'Sorry! You cannot add more than five subject data for a single student'
else
print'Insert Code';