обединяването на няколко таблици в sql
SELECT TableA.*, TableB.*, TableC.*, TableD.*
FROM TableA
JOIN TableB
ON TableB.aID = TableA.aID
JOIN TableC
ON TableC.cID = TableB.cID
JOIN TableD
ON TableD.dID = TableA.dID
WHERE DATE(TableC.date)=date(now())
обединяването на няколко таблици в sql
SELECT Books_Namn, Author_Namn, Author_Age, Store_Namn FROM books
JOIN Author ON Author_Id = Author_Author_Id
JOIN Books_has_Store ON Books_Books_Id = Books_Id
JOIN Store ON Store_Id = Store_Store_Id;
връзка с няколко условия sql
SELECT TableA.*, TableB.*, TableC.*, TableD.*
FROM TableA
JOIN TableB
ON TableB.aID = TableA.aID
JOIN TableC
ON TableC.cID = TableB.cID
JOIN TableD
ON TableD.dID = TableA.dID
WHERE DATE(TableC.date)=date(now())
-----------------------------------------
SELECT Books_Namn, Author_Namn, Author_Age, Store_Namn FROM books
JOIN Author ON Author_Id = Author_Author_Id
JOIN Books_has_Store ON Books_Books_Id = Books_Id
JOIN Store ON Store_Id = Store_Store_Id;
ОБЕДИНЯВАНЕТО на няколко операторите Select във вид на таблици
SELECT t1.ks, t1.[# Tasks], COALESCE(t2.[# Late], 0) AS [# Late]
FROM
(SELECT ks, COUNT(*) AS '# Tasks' FROM Table GROUP BY ks) t1
LEFT JOIN
(SELECT ks, COUNT(*) AS '# Late' FROM Table WHERE Age > Palt GROUP BY ks) t2
ON (t1.ks = t2.ks);