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App Inventor 2 SQLite 拓展：超流行兼容主流SQL语法的迷你本地数据库引擎...
...数据表
创建一个测试数据表，sql如下：
CREATE TABLE users (
id INTEGER PRIMARY KEY,
name TEXT,
age INTEGER);
数据表信息
这时，可以查看一下表信息：
插入数据
往 users 表中插入...
Clustered vs Non-Clustered
... PersonId means that the rows will be physically sorted by PersonId in the table, allowing an index search on this to go straight to the row (rather than a non-clustered index, which would direct you to the row's location, adding an extra step).
That said, it's unusual for the primary key not to be...
UITableView backgroundColor always gray on iPad
When I set the backgroundColor for my UITableView it works fine on iPhone (device and simulator) but NOT on the iPad simulator. Instead I get a light gray background for any color I set including groupTableViewBackgroundColor .
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How to align center the text in html table row?
I am using an HTML <table> and I want to align the text of <td> to the center in each cell.
7 Answers
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Can I split an already split hunk with git?
...nt to replace the - with a space at the beginning of these lines:
-
-form.table-form #field_teacher + label,
-form.table-form #field_producer_distributor + label {
... and delete the the following line, i.e. the one that begins with +. If you then save and exit your editor, just the removal of t...
App Inventor 2 SQLite 拓展：超流行兼容主流SQL语法的迷你本地数据库引擎...
...数据表
创建一个测试数据表，sql如下：
CREATE TABLE users (
id INTEGER PRIMARY KEY,
name TEXT,
age INTEGER);
数据表信息
这时，可以查看一下表信息：
插入数据
往 users 表中插入...
T-SQL: Using a CASE in an UPDATE statement to update certain columns depending on a condition
...tructure of your query, just the data involved. You could do this:
update table set
columnx = (case when condition then 25 else columnx end),
columny = (case when condition then columny else 25 end)
This is semantically the same, but just bear in mind that both columns will always be upda...
PreparedStatement IN clause alternatives?
...lable here.
The suggested options are:
Prepare SELECT my_column FROM my_table WHERE search_column = ?, execute it for each value and UNION the results client-side. Requires only one prepared statement. Slow and painful.
Prepare SELECT my_column FROM my_table WHERE search_column IN (?,?,?) and exe...
How do I escape reserved words used as column names? MySQL/Create Table
I am generating tables from classes in .NET and one problem is a class may have a field name key which is a reserved MySQL keyword. How do I escape it in a create table statement? (Note: The other problem below is text must be a fixed size to be indexed/unique)
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Counting the number of elements with the values of x in a vector
...
You can just use table():
> a <- table(numbers)
> a
numbers
4 5 23 34 43 54 56 65 67 324 435 453 456 567 657
2 1 2 2 1 1 2 1 2 1 3 1 1 1 1
Then you can subset it:
> a[names(a)==435]
4...