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What is the most efficient/elegant way to parse a flat table into a tree?
...port recursive queries in standard syntax.
WITH RECURSIVE MyTree AS (
SELECT * FROM MyTable WHERE ParentId IS NULL
UNION ALL
SELECT m.* FROM MyTABLE AS m JOIN MyTree AS t ON m.ParentId = t.Id
)
SELECT * FROM MyTree;
I tested recursive queries in MySQL 8.0 in my presentation Recursive ...
How to select multiple files with ?
How to select multiple files with <input type="file"> ?
9 Answers
9
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How to convert float to varchar in SQL Server
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Try using the STR() function.
SELECT STR(float_field, 25, 5)
STR() Function
Another note: this pads on the left with spaces. If this is a problem combine with LTRIM:
SELECT LTRIM(STR(float_field, 25, 5))
...
Retrieve the maximum length of a VARCHAR column in SQL Server
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Use the built-in functions for length and max on the description column:
SELECT MAX(LEN(DESC)) FROM table_name;
Note that if your table is very large, there can be performance issues.
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Oracle “Partition By” Keyword
...d then use that in a calculation against this records salary without a sub select, which is much faster.
Read the linked AskTom article for further details.
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How do I list all tables in a schema in Oracle SQL?
... schema, you need to have one or more of the following system privileges:
SELECT ANY DICTIONARY
(SELECT | INSERT | UPDATE | DELETE) ANY TABLE
or the big-hammer, the DBA role.
With any of those, you can select:
SELECT DISTINCT OWNER, OBJECT_NAME
FROM DBA_OBJECTS
WHERE OBJECT_TYPE = 'TABLE'
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ORACLE 常用日期函数 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
...的日期。如果给出一负数，返回值日期之前几个月日期。select add_months(to_date(&...ADD_MONTHS函数在输入日期上加上指定的几个月返回一个新的日期。如果给出一负数，返回值日期之前几个月日期。
select add_months(to_date('20150201','yyyymmd...
How can I change IIS Express port for a site
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In Solution Explorer, right-click the name of the application and then select Properties.
Click the Web tab.
In the Servers section, under Use Local IIS Web server, in the Project URL box change the port number.
To the right of the Project URL box, click Create Virtual Directory, and then ...
What is the best way to add options to a select from a JavaScript object with jQuery?
What is the best method for adding options to a <select> from a JavaScript object using jQuery?
36 Answers
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Entity framework linq query Include() multiple children entities
...ch allows the required depth of eager loading to be specified by providing Select expressions to the appropriate depth:
using System.Data.Entity; // NB!
var company = context.Companies
.Include(co => co.Employees.Select(emp => emp.Employee_Car))
.Inc...