“FETCH NEXT FROM Cursor” 0的时候,游标查询的结果有,游标就会将查询到的数据直接存入游标捕捉数据的变量中。 WHILE @@FETCH_STATUS=0 通常必须跟 fetch Next From xxCursor Into @xx变量 ' 一起使用 fetch Next From xxCursor Into @xx变量 作用:取游标中下一行数据赋值给变量@xx变量...
WHILE @@FETCH_STATUS=0 游标读取下一条数据是否成功。
SQL语句:SQLwhile(0=0)与while @@fetch_status=0. 第一句是SQL循环用的,这个条件下,会读取所有的记录,因为会一直循环; 第二句是游标里的,@@fetch_status=0 等于0时,说明游标是成功的.
第一句是SQL循环用的，这个条件下，会读取所有的记录，因为会一直循环 第二句是游标里的，@@fetch_status=0 等于0时，说明游标是成功的
(100)set@Cursor=cursorforselect*from@ColList2open@Cursorfetchnextfrom@Cursorinto@ColListTvar,@ColListXvarPrint'Before While => '+CAST(@@FETCH_STATUSASvarchar(32)) while (@@FETCH_STATUS=0)beginPrint'Inside while -=> '+CAST(@@FETCH_STATUSASvarchar(32))set@sql=@sql+'case when t.'+@...
WHILE FETCH_STATUS = 0 BEGIN SET amount = amount * 1.1 UPDATE sales SET amount = amount WHERE id = id FETCH NEXT FROM cur INTO id, amount END CLOSE cur DEALLOCATE cur ``` 在上面的示例中,我们首先声明了两个变量id和amount,并创建了一个游标(CURSOR),用于遍历sales表中的记录。我们使用WHILE循...
USE AdventureWorks; GO DECLARE abc CURSOR FOR SELECT * FROM Purchasing.ShipMethod; OPEN abc; FETCH NEXT FROM abc WHILE (@@FETCH_STATUS = 0) FETCH NEXT FROM abc; CLOSE abc; DEALLOCATE abc; GO 其他有效的 WHILE 条件测试可能如下所示:
price) FROM titles IF (SELECT MAX(price) FROM titles) > $50 BREAK ELSE CONTINUE END PRINT 'Too much for the market to bear'B. 在带有游标的过程中使⽤ WHILE 以下的 WHILE 结构是名为 count_all_rows 过程中的⼀部分。下例中，该 WHILE 结构测试⽤于游标的函数 @@FETCH_STATUS 的返回 ...
function fetchData(callback) { var xhr = new XMLHttpRequest(); xhr.open('GET', 'https://example.com/api/data', true); xhr.onreadystatechange = function() { if (xhr.readyState === 4 && xhr.status === 200) { var data = JSON.parse(xhr.responseText); callback(data); } }; xhr...
But, cant figure out second case - because, after query changes react-query doing fetch of new results and data from useQuery is empty as result I get default empty array and in that case falls to that condition -if (isLoading && !data.length ) ...