大约有 9,000 项符合查询结果（耗时：0.0310秒） [XML]
How to select from subquery using Laravel Query Builder?
I'd like to get value by the following SQL using Eloquent ORM.
7 Answers
7
...
What is the most efficient/elegant way to parse a flat table into a tree?
...
Now that MySQL 8.0 supports recursive queries, we can say that all popular SQL databases support recursive queries in standard syntax.
WITH RECURSIVE MyTree AS (
SELECT * FROM MyTable WHERE ParentId IS NULL
UNION ALL
SELECT...
PDO Prepared Inserts multiple rows in single query
I am currently using this type of SQL on MySQL to insert multiple rows of values in one single query:
22 Answers
...
varbinary to string on SQL Server
...rent things.
If the varbinary is the binary representation of a string in SQL Server (for example returned by casting to varbinary directly or from the DecryptByPassPhrase or DECOMPRESS functions) you can just CAST it
declare @b varbinary(max)
set @b = 0x5468697320697320612074657374
select cast(@...
SQL Server - When to use Clustered vs non-Clustered Index?
...k a good clustered index.
It's the most replicated data structure in your SQL Server database. The clustering key will be part of each and every non-clustered index on your table, too.
You should use extreme care when picking a clustering key - it should be:
narrow (4 bytes ideal)
unique (it's t...
postgres default timezone
I installed PostgreSQL 9 and the time it is showing is 1 hour behind the server time.
7 Answers
...
How to randomly select rows in SQL?
I am using MSSQL Server 2005. In my db, I have a table "customerNames" which has two columns "Id" and "Name" and approx. 1,000 results.
...
How to generate the “create table” sql statement for an existing table in postgreSQL
I have created a table in postgreSQL. I want to look at the SQL statement used to create the table but cannot figure it out.
...
How to get cumulative sum
...in @t t2 on t1.id >= t2.id
group by t1.id, t1.SomeNumt
order by t1.id
SQL Fiddle example
Output
| ID | SOMENUMT | SUM |
-----------------------
| 1 | 10 | 10 |
| 2 | 12 | 22 |
| 3 | 3 | 25 |
| 4 | 15 | 40 |
| 5 | 23 | 63 |
Edit: this is a generalized...
Naming of ID columns in database tables
...
ID is a SQL Antipattern.
See http://www.amazon.com/s/ref=nb_sb_ss_i_1_5?url=search-alias%3Dstripbooks&field-keywords=sql+antipatterns&sprefix=sql+a
If you have many tables with ID as the id you are making reporting that muc...