Uw vraag:
SELECT Email, Phonenumber
FROM EMPLOYEE
WHERE COUNT(
ID = (SELECT ID_Num
FROM SCHEDULE
WHERE Start_Time <= 12:07 AND End_Time >= 12:07)
AND Shopn = (SELECT Shopname
FROM SHOP
WHERE Shoptype = ‘market’) ) > 2
Problemen :
- Het lijkt erop dat je id probeert te selecteren met de operator "=", wat niet lukt als er meerdere items worden geretourneerd door een innerlijke query.
- U kunt geen aggregatieoperatoren toevoegen aan de waar-clausule.
Waarschijnlijk antwoord:
select Email, Phonenumber
FROM EMPLOYEE
WHERE ID in (SELECT ID_Num
FROM SCHEDULE
WHERE Start_Time <= '12:07' AND End_Time >= '12:07')
AND Shopn in (SELECT Shopname
FROM SHOP
WHERE Shoptype = 'market')
and (
select count(distinct id)
FROM EMPLOYEE
WHERE ID in (SELECT ID_Num
FROM SCHEDULE
WHERE Start_Time <= '12:07' AND End_Time >= '12:07')
AND Shopn in (SELECT Shopname
FROM SHOP
WHERE Shoptype = 'market')) > 2;