tricky sql queries

Partii:sql BasicsCHAPTER 4Creating a simple Querydescribes a way to create SQL the technology of the statement -- "Request/translation/clean up/sql "The SELECT operationin SQL can broken down into three smaller operations,Which we'll referto as the select statement,the Select expression,and the SelectQuery.The first layer contains one layer , nesting with each o

)) It's a simple paging! Select Htname as type, UNAME as name, dname as County, SNAME as street from hos_house left outerJoin Sys_user on Sys_user. Uid=hos_house. UidJoin Hos_street on Hos_street. Sid=hos_house. SidJoin Hos_district on Hos_district. Did=hos_street. SdidJoin Hos_type on Hos_type. Htid=hos_house. Htidwhere Hos_district. did in(Select Sdid from Hos_street where Sdid in(Select SID from Hos_house Group by SID have (COUNT (*) >=1)) Group by Sdid have (COUNT (*) >=2)) Order BY Sdid Thi

byValExecution Result:Case-Search expression:SELECTOrderID, CustID, Val, Case whenVal 1000.00 Then ' less Then' whenValbetween 1000.00 and 3000.00 Then 'between' whenVal> 3000.00 Then 'More than' ELSE 'Unknown' END asvaluecategory fromSales.ordervalues;Execution Result:Sorting rulesIf you want the collation of a column to be case-insensitive, you can modify the collation of an expression as follows:SELECT Empid, FirstName, LastName fro

Label:That day: SELECT * from T_news where DateDiff (Day,addtime,getdate ()) =0 Last three days: SELECT * from T_news where DateDiff (Day,addtime,getdate ()) Week: SELECT * from T_news WHERE (DATEPART (wk, addtime) = DATEPART (wk, GETDATE ())) and (DATEPART (yy, addtime) = DATEPART (yy, GET DATE ())) Note: You cannot use the DateDiff difference at this time as 7, because DateDiff only represents the number of intervals Month: SELECT * from T_news WHERE (DATEPART (yy, addtime) = DATEPART (yy, GE

Because a small feature of recent projects requires a comparison of current data and history today. On the internet also looked for a long time, many are to achieve within one months, all the data in a year, last night suddenly found the following implementation method, in SQL Server2008 tried, it is I want results. Therefore wrote an essay, if later still need to be able to find, in addition also hope can help the people who need.SELECT * from the hi

changes only need to change the innermost layer is OK. For example, to query for a specified column: Modify the innermost select Ename,sal from emp; Sort by salary column: Select Ename,sal from EMP ordered by Sal; all you need to do is modify the innermost layer. A common paging method in 3.SQLServerLet's use the example of the employee table to talk about the implementation of paging in SQL Serveruse of the first top:SQL Server implements the first

generic list. Use tolist VaRQ =FromEInDB. EmployeesWhereE. hiredate> =NewDatetime(1994, 1, 1)SelectE;ListEmployee> Qlist = Q. tolist (); 4. todictionary: converts a sequence into a dictionary. You can use the enumerable. todictionary VaRQ =FromPInDB. ProductsWhereP. unitsinstock SelectP;DictionaryInt,Product> Qdictionary =Q. todictionary (P => P. productid );Foreach(IntKeyInQdictionary. Keys){Console. Writeline (key );} Statement Description: In this example, the direct key expression

How to dynamically number rows and add row numbers in SQL is a classic problem in database queries. How to dynamically number rows and add row numbers in SQL is a classic problem in database queries. (1) display and sort row numbers 1. SQL Server row number A.

Implementation methods of Database SQL recursive queries in different databases, SQL Recursion This article describes how to implement SQL recursive queries in different databases. For more information, see the following. For example, the table structure data is as follows:

It's cool to manipulate the database on play with functional framework slick. But sometimes, because of some special scenarios, you have to use native SQL. Fortunately slick support this notation, you can look at slick official documents, slick Plain SQL queriesHttp://slick.lightbend.com/doc/3.1.1/sql-to-slick.html#slick-plain-