在SQL中,WHILE循环通常用于在存储过程或脚本中执行重复的操作。当你想要基于某些条件重复执行一组SQL语句时,可以使用WHILE循环。下面是一个使用WHILE循环从SELECT语句获取数据并将其插入到另一张表中的基本示例。 基础概念 WHILE循环:在SQL中,WHILE循环允许你重复执行一段代码块,直到指定的条件不再为真。 SELECT
Summary: in this tutorial, you will learn about PL/SQL WHILE loop statement to execute a sequence of statements as long as a specified condition is TRUE. Introduction to PL/SQL WHILE loop statement PL/SQL WHILE loop is a control structure that repeatedly executes a code block as long as a...
在上面的test_mysql_while_loop存储过程中: 首先,重复构建str字符串,直到x变量的值大于5。 然后,使用SELECT语句显示最终的字符串。 要注意,如果不初始化x变量的值,那么它默认值为NULL。 因此,WHILE循环语句中的条件始终为TRUE,并且您将有一个不确定的循环,这是不可预料的。 下面来测试test_mysql_while_loopstore...
ID || ' '; END LOOP; --拼接主SQL TARGET_RESULTS := TARGET_RESULTS || 'FROM (SELECT a.PRO_NAME,a.CLASS_NAME,a.ID,a.MAIN_DATA_PRO_CODE,b.TIME '; TARGET_RESULTS := TARGET_RESULTS || 'FROM IEW_V_PRO_USER a LEFT JOIN (SELECT DISTINCT PROJECTID,TIME from V_IEW_ACC_DETAIL_...
(i) := 'row'||i; end loop; sql_stmt := 'insert into test(row_num,row_text) values (:1,:2)'; forall i in 1..10 execute immediate sql_stmt using row_num_tab(i),row_text_tab(i); commit; select count(*) into v_total from test; dbms_output.put_line(v_total||' rows ...
mysql> select * from t1// +——-+ | filed | +——-+ | 0 | | 1 | | 2 | | 3 | | 4 | +——-+ 5 rows in set (0.00 sec) 一行就是执行结果,实际的作用和使用while编写的存储过程一样,都是插入5行数据。 再来看一下第三个循环控制语句LOOP……END LOOP。编写一个存储过程程序如下:...
In the stored procedure above: First, we buildstrstring repeatedly until the value of thexvariableis greater than5. Then, we display the final string using theSELECT statement. Notice that if we don’t initialize x variable, its default value isNULL. Therefore the condition in theWHILEloop ...
Then, we display the final string using the SELECT statement. Notice that if we don’t initialize x variable, its default value is NULL. Therefore the condition in the WHILE loop statement is always TRUE and you will have a indefinite loop, which is not expected. REPEAT loop The syntax of...
"SELECT INTO" with indexes? "Simple" SQL to check for alpha or numeric charcters isn't working right "String or binary data would be truncated.\r\nThe statement has been terminated." "String or binary data would be truncated" and field specifications “Unable to enlist in the transaction”...
Finally got it to work thanks to Peter's suggestion on using the command line to call the sp. This gave much more info on why the sp was not working. I also had to update the first column in my select statement in the prepared sql so that it would insert the name of the table be...