I think that you are after this: SELECT image_id FROM list WHERE (style_id, style_value) IN ((24,’red’),(25,’big’),(27,’round’)) GROUP BY image_id HAVING count(distinct style_id, style_value)=3 You can’t use AND, because values can’t be 24 red and 25 big and 27 round at the same time in the same row, but you need to check the presence of … Read more
They are not the same thing. Consider these queries: SELECT * FROM Orders LEFT JOIN OrderLines ON OrderLines.OrderID=Orders.ID WHERE Orders.ID = 12345 and SELECT * FROM Orders LEFT JOIN OrderLines ON OrderLines.OrderID=Orders.ID AND Orders.ID = 12345 The first will return an order and its lines, if any, for order number 12345. The second will return … Read more
I wouldn’t use performance as the deciding factor here – and quite honestly, I don’t think there’s any measurable performance difference between those two cases, really. I would always use case #2 – why? Because in my opinion, you should only put the actual criteria that establish the JOIN between the two tables into the … Read more
if you don’t use the WHERE clause all the records on the table will be affected
from item in db.vw_Dropship_OrderItems where (listStatus != null ? listStatus.Contains(item.StatusCode) : true) && (listMerchants != null ? listMerchants.Contains(item.MerchantId) : true) select item; Might give strange behavior if both listMerchants and listStatus are both null.
I changed the query to use EXISTS because if there’s more than one location associated with a POST, there’d be duplicate POST records that’d require a DISTINCT or GROUP BY clause to get rid of… The non-sargable This will perform the worst of the possible solutions: SELECT p.* FROM POSTS p WHERE EXISTS(SELECT NULL FROM … Read more
var query = someList.Where(a => (someCondition)? a == “something” : true); so, if ‘someCondition’ is false, ‘Where’ will be skipped.
I have encountered a similar issue in my project. The way I choose to implement it is a bit different for two reasons: If at one point in time Sequelize decides to implement sub queries – the syntax is ready. Use Sequelize protection against SQL injection. Here is my code snippet, hope it helps. Sequelize … Read more
The answer is NO difference, but: I will always prefer to do the following. Always keep the Join Conditions in ON clause Always put the filter’s in where clause This makes the query more readable. So I will use this query: SELECT value FROM table1 INNER JOIN table2 ON table1.id = table2.id WHERE table1.id = … Read more