having

问题 This is the database: EMPLOYEE (fmane, minit, lname, ssn, birthdate, address, sex, salary, superssn, dno) KEY: ssn DEPARTMENT (dname, dnumber, mgrssn, mgrstartdate) KEY: dnumber. PROJECT (pname, pnumber, plocation, dnum) KEY: pnumber. WORKS_ON (essn, pno, hours) KEY: (essn, pno) DEPENDENT (essn, dependent-name, sex, bdate, relationship) KEY: (essn, dependent-name) The question asked is... Give the last name and SSN of the unmarried employees who work on two or more projects. SELECT e.Lname, e

问题 Somebody already helped me with this query but I made an adaptation and I get a problem : SELECT AVG(tyd.price) AS avg_price, COUNT(tyd.id_product) AS cnt, tyd.id_marchand, tyd.id_product, catalog.price AS c_price, tyd.price AS t_price, tyd.amount AS t_am, pro_tyd.amount AS p_am, pro_tyd.price AS p_price, catalog.img_src, tyd.step, tyd.login AS tyd_l FROM catalog INNER JOIN tyd ON catalog.id_marchand = tyd.id_marchand AND catalog.id_product = tyd.id_product AND tyd.step = "1" INNER JOIN pro

问题 Let's put GROUP BY aside for a second. In normal queries (without GROUP BY ), what is the semantic difference? Why does this answer work? (put an alias in a HAVING clause instead of WHERE ) 回答1: HAVING operates on the summarized row - WHERE is operating on the entire table before the GROUP BY is applied. (You can't put GROUP BY aside, HAVING is a clause reserved for use with GROUP BY - leaving out the GROUP BY doesn't change the implicit action that is occurring behind the scenes). It's also

问题 This question already has answers here : Closed 8 years ago . Possible Duplicate: SQL: What's the difference between HAVING and WHERE? I have seen various discussions on WHERE and HAVING . I still have a question: is HAVING used only when considering aggregates, or can it be used in more general terms: whenever you have created or aliased a field in your query? I know that WHERE should always be used when possible. 回答1: HAVING specifies a search for something used in the SELECT statement. In

问题 The following criteria query calculates the average of rating of different groups of products. CriteriaBuilder criteriaBuilder=entityManager.getCriteriaBuilder(); CriteriaQuery<Tuple>criteriaQuery=criteriaBuilder.createQuery(Tuple.class); Metamodel metamodel=entityManager.getMetamodel(); EntityType<Product>entityType=metamodel.entity(Product.class); Root<Product>root=criteriaQuery.from(entityType); SetJoin<Product, Rating> join = root.join(Product_.ratingSet, JoinType.LEFT); Expression<Number

问题 For what would be this query in SQL (to find duplicates): SELECT userId, name FROM col GROUP BY userId, name HAVING COUNT(*)>1 I performed this simple query in MongoDB: res = db.col.group({key:{userId:true,name:true}, reduce: function(obj,prev) {prev.count++;}, initial: {count:0}}) I've added a simple Javascript loop to go over the result set, and performed a filter to find all the fields with a count > 1 there, like so: for (i in res) {if (res[i].count>1) printjson(res[i])}; Is there a

问题 I have the following database table Here is my sample data I have for it. What I am trying to figure out how to do is how to write a query to select all apntoken for userid='20' grouping by deviceid and then by apntoken as well (except that it should show the most recent apntoken). Some queries I have tried are this. SELECT DISTINCT apntoken,deviceid,created FROM `distribution_mobiletokens` WHERE userid='20' GROUP BY deviceid This returns the following result. Notice the date is not the

问题 i have trouble with mysql, i dont find the way to do it maybe i dont know the good mysql keyword mysql5 +----------+------------+----------+ | ID | FOREIGNKEY | TRAINER | +----------+------------+----------+ | ... | ... | ... | | 475 | 254 | NULL | | 476 | 254 | NULL | | 477 | 254 | NULL | | 478 | 286 | NULL | | 479 | 286 | FREE | | 480 | 286 | FREE | | 481 | 401 | FREE | | 482 | 401 | 1 | | 483 | 401 | FREE | | 484 | 405 | NULL | | 485 | 405 | 1 | | 486 | 405 | 5 | | 487 | 405 | FREE | | 488

问题 This question is different to a commonly asked question about ordering the final results by the IN clause. I would like to force the results returned by the query that contains the IN clause, to match the order of the IN clause. This is the original question that I am working from. I'd like to alter the query below so that a row containing progress=2 occurs before progress=4 and progress=7 for each session_id when ordering the formation_page_hits table by datetime . Here is the current query:

问题 I'm having problems with what I thought was a simple query to count records: SELECT req_ownerid, count(req_status_lender) AS total6 FROM bor_requests WHERE (req_status_lender = 0 AND req_status_borrower = 0) OR (req_status_lender = 1 AND req_status_borrower = 1) GROUP BY req_ownerid HAVING req_ownerid = 70 I thought this would count all the records where (req_status_lender = 0 AND req_status_borrower = 0) and (req_status_lender = 1 AND req_status_borrower = 1) and then give me the total but