CASE selector WHEN selector_value_1 THEN statements_1 WHEN selector_value_2 THEN statements_2 ... WHEN selector_value_n THEN statements_n [ ELSE else_statements ] END CASE;]
The simple CASE statement runs the first statements for which selector_value equals selector. Remaining conditions are not evaluated. If no selector_value equals selector, the CASE statement runs else_statements if they exist and raises the predefined exception CASE_NOT_FOUND otherwise.
CASE WHEN condition_1 THEN statements_1 WHEN condition_2 THEN statements_2 ... WHEN condition_n THEN statements_n [ ELSE else_statements ] END CASE;]
The searched CASE
statement runs the first statements
for which condition
is true. Remaining conditions are not evaluated. If no condition
is true, the CASE
statement runs else_statements
if they exist and raises the predefined exception CASE_NOT_FOUND
otherwise.
DECLARE grade CHAR(1); BEGIN grade := 'B'; CASE WHEN grade = 'A' THEN DBMS_OUTPUT.PUT_LINE('Excellent'); WHEN grade = 'B' THEN DBMS_OUTPUT.PUT_LINE('Very Good'); WHEN grade = 'C' THEN DBMS_OUTPUT.PUT_LINE('Good'); WHEN grade = 'D' THEN DBMS_OUTPUT.PUT_LINE('Fair'); WHEN grade = 'F' THEN DBMS_OUTPUT.PUT_LINE('Poor'); END CASE; EXCEPTION WHEN CASE_NOT_FOUND THEN DBMS_OUTPUT.PUT_LINE('No such grade'); END; /
The lower and upper bounds of a FOR LOOP statement can be either numeric literals, numeric variables, or numeric expressions. If a bound does not have a numeric value, then PL/SQL raises the predefined exception VALUE_ERROR.
存储过程死循环
1.找到运行存储过程的session
select * from v$session;
如果长时间运行,
select * from v$locked_object;
2.删除该会话
alter system kill session 'sid,serial#';
If the SELECT INTO statement returns no rows, PL/SQL raises the predefined exception NO_DATA_FOUND immediately, before you can check SQL%NOTFOUND.
If a SELECT INTO statement without a BULK COLLECT clause returns multiple rows, PL/SQL raises the predefined exception TOO_MANY_ROWS
After closing a cursor, you cannot fetch records from its result set or reference its attributes. If you try, PL/SQL raises the predefined exception INVALID_CURSOR.
If an explicit cursor is not open, referencing any attribute except %ISOPEN raises the predefined exception INVALID_CURSOR.
You can reopen a closed cursor. You must close an explicit cursor before you try to reopen it. Otherwise, PL/SQL raises the predefined exception CURSOR_ALREADY_OPEN.
After opening a cursor variable, you can fetch the rows of the query result set with the FETCH statement.
The return type of the cursor variable must be compatible with the into_clause of the FETCH statement. If the cursor variable is strong, PL/SQL catches incompatibility
at compile time. If the cursor variable is weak, PL/SQL catches incompatibility at run time, raising the predefined exception ROWTYPE_MISMATCH before the first fetch.
The DUP_VAL_ON_INDEX Exception (ORA-00001) occurs when a program attempts to store a duplicate value or values in a database column that is constrained by a unique index.