在PLSQL SELECT语句中使用变量

Question

我有一个查询ReportStartDate和ReportEndDate的查询,所以我想我会在PLSQL中使用变量.不知道我在这里缺少什么,但我收到一个错误:

CLEAR;
DECLARE
    varReportStartDate Date := to_date('05/01/2010', 'mm/dd/yyyy');
    varReportEndDate Date := to_date('05/31/2010', 'mm/dd/yyyy');
BEGIN

    SELECT 
          'Value TYPE', 
          1 AS CountType1, 
          2 AS CountType2, 
          3 AS CountType3 
    FROM DUAL;

    SELECT COUNT (*) 
    FROM CDR.MSRS_E_INADVCH

    WHERE 1=1
    AND ReportStartDate = varReportStartDate 
    AND ReportEndDate = varReportEndDate 
    ;
END;
/

错误是:

Error starting at line 2 in command:
Error report:
ORA-06550: line 6, column 5:
PLS-00428: an INTO clause is expected in this SELECT statement
ORA-06550: line 8, column 5:
PLS-00428: an INTO clause is expected in this SELECT statement
06550. 00000 -  "line %s, column %s:\n%s"
*Cause:    Usually a PL/SQL compilation error.
*Action:

这种情况发生在Toad以及SQL Developer中.

在WHERE子句中使用变量的正确方法是什么？

Answer 1

您不能直接在PL/SQL块中使用SQL语句(除非您使用EXECUTE IMMEDIATE).需要将列提取到变量中(这是PL/SQL告诉您的PLS-00428: an INTO clause is expected in this SELECT statement错误).所以你必须重写你的陈述,如下所示.

SELECT 
      'Value TYPE', 
      1 AS CountType1, 
      2 AS CountType2, 
      3 AS CountType3 
INTO 
     V_VALUE_TYPE,
     V_CountType1,
     V_CountType2,
     V_CountType3
FROM DUAL;

SELECT COUNT(*) 
   INTO V_COUNT    
FROM CDR.MSRS_E_INADVCH
WHERE 1=1
AND ReportStartDate = varReportStartDate 
AND ReportEndDate = varReportEndDate 

一定要添加异常处理程序,因为PL/SQL只需要返回1行.如果语句没有返回任何行,则会遇到NO_DATA_FOUND异常 - 如果语句获取的行太多,则会遇到TOO_MANY_ROWS异常.