LOOP:先执行再判断,至少执行一次; WHILE LOOP:先判断再执行,如果不满足条件,就不执行 FOR循环:已知要循环的次数. 如果明确知道循环次数,使用FOR循环; 如果不知道循环次数,但是知道循环结束条件,使用LOOP循环. 循环控制:EXIT与CONTINUE语句完成。 PL/SQL程序与其他编程语言一样,也拥有自己的三种程序结构:顺序结构、分...
(100); CURSOR c_num3 IS SELECT NAME FROM test_t WHERE ROWNUM < 600000; BEGIN OPEN c_num3; FETCH c_num3 INTO v_num3; WHILE c_num3%FOUND LOOP -- 能找到数据则执行循环内语句 FETCH c_num3 INTO v_num3; END LOOP; CLOSE c_num3; END; -- for DECLARE v_num2 VARCHAR2(100); ...
WHILE DO dropprocedureifexistsp_while_do;createprocedurep_while_do()begindeclareiint;seti=1;whilei<=10doselectconcat('index :', i);seti=i+1;endwhile;end; call p_while_do(); FOR LOOP dropprocedureifexistsp_for_loop;createprocedurep_for_loop()begindeclareiint;seti=1; loop_example : l...
Dbms_Output.put_line('loop也就是do-while');exitwhen9>0;endloop;end; 结果: for循环 --forbeginforiin1..6loop Dbms_Output.put_line('i:'||i);endloop;end; 结果: while循环 --whilebeginwhile6>0loop Dbms_Output.put_line('6>0');exit;endloop;end; exit:跳出当前循环,使循环结束(相当与...
FOR循环用法,以下是SQL源码: DECLARE x number; --声明变量BEGIN x := 1; --给初值 FOR x IN REVERSE 1 .. 10 LOOP --reverse由大到小 DBMS_OUTPUT.PUT_LINE('x=' || x); END LOOP; DBMS_OUTPUT.PUT_LINE('end loop x=' || x); --x=1END; ...
TARGET_RESULTS :=TARGET_RESULTS||'ON B.ID = C.PROJECTID AND C.YEAR_DATE = D.TIME) T ORDER BY ID,PROJECTNAME,TIME )C ON A.ID = C.ID AND B.TIME = C.TIME ORDER BY a.ID,b.TIME'; TARGET_RESULTS :=TARGET_RESULTS||') '||ALIAS||' ';--循环拼接关联SQLFORTEMPINDATA LOOP--给...
C.PROJECTID AND C.YEAR_DATE = D.TIME) T ORDER BY ID,PROJECTNAME,TIME )C ON A.ID = C.ID AND B.TIME = C.TIME ORDER BY a.ID,b.TIME'; TARGET_RESULTS := TARGET_RESULTS || ') ' || ALIAS || ' '; --循环拼接关联SQL FOR TEMP IN DATA LOOP --给待拼接的字段赋值 STR := ...
...SQL WHILE SIGNS > 0 LOOP --取当前字段 SELECT SUBSTR(STR,1,INSTR(STR,',') - 1 ) INTO CURRENT_VALUE FROM...QUERY_ITEMS := ''; --循环拼接SQL WHILE SIGNS > 0 LOOP --取当前字段 SELECT SUBSTR(STR,1,INSTR(STR,...EXECUTE IMMEDIATE 执行动态语句,可以用于执行动态拼接好的SQL。
TheLEAVEstatement allows you to exit the loop immediately without waiting for checking the condition. TheLEAVEstatement works like thebreakstatement in other languages such as PHP, C/C++, Java, etc. TheITERATEstatement allows you to skip the entire code under it and start a new iteration. The...
Summary: in this tutorial, you will learn how to use various loop statements in MySQL including WHILE, REPEAT and LOOP to run a block of code repeatedly based on a condition. MySQL provides loop statements that allow you to execute a block of SQL code repeatedly based on a condition. ...