sqlite-如何获得单行结果? (luaSQLite3) [英] sqlite - how do I get a one row result back? (luaSQLite3)

问题描述

如何从sql语句获取单行结果(例如，以表/数组的形式).使用Lua Sqlite(LuaSQLite3).例如，这个:

How can I get a single row result (e.g. in form of a table/array) back from a sql statement. Using Lua Sqlite (LuaSQLite3). For example this one:

SELECT * FROM sqlite_master WHERE name ='myTable';

到目前为止，我注意到:

So far I note:

• 使用"nrows"/"rows"可以使迭代器返回
• 使用"exec"似乎没有返回结果(?)

具体问题如下:

问题1-如何获取单行(例如第一行)结果?

Q1 - How to get a single row (say first row) result back?

Q2-如何获得行数? (例如num_rows_returned = db:XXXX(sql))

Q2 - How to get row count? (e.g. num_rows_returned = db:XXXX(sql))

推荐答案

以下是获取返回计数的演示:

Here is a demo of getting the returned count:

> require "lsqlite3"
> db = sqlite3.open":memory:"
> db:exec "create table foo (x,y,z);"
> for x in db:urows "select count(*) from foo" do print(x) end
0
> db:exec "insert into foo values (10,11,12);"
> for x in db:urows "select count(*) from foo" do print(x) end
1
> 

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