为什么我这么写EXEC SQL PREPARE stmt1 from :TmSqlStr;报错

EXEC SQL PREPARE stmt1 from :TmSqlStr;
EXEC SQL DECLARE GetPrepayCur1 CURSOR FOR stmt1;
EXEC SQL OPEN GetPrepayCur1 USING :iPhoneNo;
提示我：Semantic error at line 130, column 33, file RChaPrepay.cp:
EXEC SQL PREPARE stmt1 from :TmSqlStr;
................................1
PCC-S-02322, found undefined identifier
Semantic error at line 130, column 27, file RChaPrepay.cp:
EXEC SQL PREPARE stmt1 from :TmSqlStr;

相关了解……