大约有 47,000 项符合查询结果(耗时:0.0341秒) [XML]

https://stackoverflow.com/ques... 

Count number of records returned by group by

... You can do both in one query using the OVER clause on another COUNT select count(*) RecordsPerGroup, COUNT(*) OVER () AS TotalRecords from temptable group by column_1, column_2, column_3, column_4 share ...
https://stackoverflow.com/ques... 

SQL Server Insert if not exists

..., Assunto, Data) VALUES (@_DE, @_ASSUNTO, @_DATA) WHERE NOT EXISTS ( SELECT * FROM EmailsRecebidos WHERE De = @_DE AND Assunto = @_ASSUNTO AND Data = @_DATA); END replace with BEGIN IF NOT EXISTS (SELECT * FROM EmailsRecebidos ...
https://stackoverflow.com/ques... 

Rails select helper - Default selected value, how?

... This should do it: <%= f.select :project_id, @project_select, :selected => params[:pid] %> share | improve this answer | ...
https://stackoverflow.com/ques... 

Select Multiple Fields from List in Linq

... Anonymous types allow you to select arbitrary fields into data structures that are strongly typed later on in your code: var cats = listObject .Select(i => new { i.category_id, i.category_name }) .Distinct() .OrderByDescending(i => i.c...
https://stackoverflow.com/ques... 

Check if a row exists, otherwise insert

... I assume a single row for each flight? If so: IF EXISTS (SELECT * FROM Bookings WHERE FLightID = @Id) BEGIN --UPDATE HERE END ELSE BEGIN -- INSERT HERE END I assume what I said, as your way of doing things can overbook a flight, as it will insert a new row when there are 1...
https://stackoverflow.com/ques... 

SQL query to find record with ID not in another table

... Try this SELECT ID, Name FROM Table1 WHERE ID NOT IN (SELECT ID FROM Table2) share | improve this answer | ...
https://stackoverflow.com/ques... 

SQL Query to concatenate column values from multiple rows in Oracle

...on on string aggregation techniques. A very common one is to use LISTAGG: SELECT pid, LISTAGG(Desc, ' ') WITHIN GROUP (ORDER BY seq) AS description FROM B GROUP BY pid; Then join to A to pick out the pids you want. Note: Out of the box, LISTAGG only works correctly with VARCHAR2 columns. ...
https://stackoverflow.com/ques... 

How to get a date in YYYY-MM-DD format from a TSQL datetime field?

... SELECT CONVERT(char(10), GetDate(),126) Limiting the size of the varchar chops of the hour portion that you don't want. share | ...
https://stackoverflow.com/ques... 

What's the difference between INNER JOIN, LEFT JOIN, RIGHT JOIN and FULL JOIN? [duplicate]

...These pictures don't do it for me. Why is the top right picture not simply SELECT * FROM TableA;? Why is the top left picture not simply SELECT * FROM TableB;? Why is the top middle picture not SELECT * FROM A INTERSECT SELECT * FROM B ? etc – onedaywhen Sep 9 ...
https://stackoverflow.com/ques... 

PostgreSQL return result set as JSON array?

... TL;DR SELECT json_agg(t) FROM t for a JSON array of objects, and SELECT json_build_object( 'a', json_agg(t.a), 'b', json_agg(t.b) ) FROM t for a JSON object of arrays. List of objects This section de...