大约有 40,000 项符合查询结果（耗时：0.0435秒） [XML]
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...
Which is fastest? SELECT SQL_CALC_FOUND_ROWS FROM `table`, or SELECT COUNT(*)
...irm this - I just updated a query with 4 joins on a 168,000 row database. Selecting just the first 100 rows with a SQL_CALC_FOUND_ROWS took over 20 seconds; using a separate COUNT(*) query took under 5 seconds (for both count + results queries).
– Sam Dufel
Ju...
How to get sp_executesql result into a variable?
...
DECLARE @ParmDefinition nvarchar(500);
DECLARE @tablename nvarchar(50)
SELECT @tablename = N'products'
SELECT @sSQL = N'SELECT @retvalOUT = MAX(ID) FROM ' + @tablename;
SET @ParmDefinition = N'@retvalOUT int OUTPUT';
EXEC sp_executesql @sSQL, @ParmDefinition, @retvalOUT=@retval OUTPUT;
SE...
Mysql: Select rows from a table that are not in another
How to select all rows in one table that do not appear on another?
8 Answers
8
...
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...
MySQL select one column DISTINCT, with corresponding other columns
I want to select DISTINCT results from the FirstName column, but I need the corresponding ID and LastName .
12 Answe...
Javascript/jQuery: Set Values (Selection) in a multiple Select
I have a multiple select:
8 Answers
8
...
How to generate a range of numbers between two numbers?
...
Select non-persisted values with the VALUES keyword. Then use JOINs to generate lots and lots of combinations (can be extended to create hundreds of thousands of rows and beyond).
SELECT ones.n + 10*tens.n + 100*hundreds.n +...
1052: Column 'id' in field list is ambiguous
...and tbl_section which has both the id field in them. How do I go about selecting the id field, because I always get this error:
...
Programmatically select text in a contenteditable HTML element?
In JavaScript, it's possible to programmatically select text in an input or textarea element. You can focus an input with ipt.focus() , and then select its contents with ipt.select() . You can even select a specific range with ipt.setSelectionRange(from,to) .
...