exists

May be is a very stupid question, What is the best way to check if a field of a document in elasticsearch exists? I can't find anything in the documentation. For example if this document doesn't have the field/key "price" I don't want to return in the result. { "updated": "2015/09/17 11:27:27", "name": "Eye Shadow", "format": "1.5 g / 0.05 oz", } What I can do? Thanks You can use the exists filter combined with a bool/must filter like this: { "query": { "filtered": { "filter": { "bool": { "must": [ { "exists": { "field": "price" } }, ... <-- your other constraints, if any ] } } } } }

1.数据的操作 -- 更新名字为4为的用户，让其年龄+100 UPDATE cms_user SET age = age + 100 WHERE username LIKE '____'; -- 更新前三条记录，让已有年龄+20 UPDATE cms_user SET age = age + 20 LIMIT 3; 注意：不能使用偏移量的分页限制方式。 -- 删除用户性别为男的用户，按照年龄降序排列，删除前2条记录 DELETE FROM cms_user WHERE sex = '男' ORDER BY age DESC LIMIT 2; 2.连接查询 -- 查询cms_user id,username -- provinces,proName SELECT cms_user.id,cms_user.username,provinces.proName FROM cms_user,provinces;-- 这样得到的结果是一个笛卡尔积的形式 SELECT cms_user.id,cms_user.username,provinces.proName FROM cms_user,provinces WHERE cms_user.proId = provinces.`id`; -- 内连接的方式进行查询 SELECT u.`id`,u.`username`,p.`proName`

I get an error when I do the following: if(Session["value"] != null) { // code } The error i get is this: Object reference not set to an instance of an object. Why is this? I always check my session this way? I am using the MVC Framework, does this has something to do with it? EDIT: The code is in the constructor of a Controller: public class MyController : ControllerBase { private int mVar; public MyController() { if (Session["value"] != null) { mVar= (int)Session["value"]; } } } The session only really exists during the processing of an action - I wouldn't expect it to be valid in the

I'm using MySQL 5.1 hosted at my ISP. This is my query mysql_query(" IF EXISTS(SELECT * FROM licensing_active WHERE title_1='$title_1') THEN BEGIN UPDATE licensing_active SET time='$time' WHERE title_1='$title_1') END ELSE BEGIN INSERT INTO licensing_active(title_1) VALUES('$title_1') END ") or die(mysql_error()); The error is ... check the manual that corresponds to your MySQL server version for the right syntax to use near 'IF EXISTS(SELECT * FROM licensing_active WHERE title_1='Title1') THEN ' at line 1 My actual task involves WHERE title_1='$title_1' AND title_2='$title_2' AND version='

How do I only select the stores that don't have client 5 ? StoreId ClientId ------- --------- 1 4 1 5 2 5 2 6 2 7 3 8 I'm trying something like this: SELECT SC.StoreId FROM StoreClients INNER JOIN StoreClients SC ON StoreClients.StoreId = SC.StoreId WHERE SC.ClientId = 5 GROUP BY StoreClients.StoreId That seems to get me all the stores that have that client but I can't do the opposite because if I do <> 5 ill still get Store 1 and 2 which I don't want. I'm basically trying to use this result in another query's EXISTS IN clause One way: SELECT DISTINCT sc.StoreId FROM StoreClients sc WHERE NOT

I'm using MySQL 5.1, and I have a query that's roughly of the form: select count(*) from mytable where a = "foo" and b = "bar"; In my program, the only thing that it checks is whether this is zero or nonzero. If I convert this into: select exists(select * from mytable where a = "foo" and b = "bar"); is MySQL smart enough to stop searching when it hits the first one? Or is there some other way to communicate to MySQL that my intent is simply to find out if any records match this, and I don't need an exact count? Yes, MySQL (indeed all database systems as far as I'm aware) will stop processing