There is a SQL code like this:
Get query results from C #:
There are two parameters in the SQL code, all of which are string types, and the above C # code is the parameter required to generate the Oracle SQL code. The results of the operation are as follows:
What a mistake! It's not a result of a lot of trying!
The weird thing about this error is that when the value of Phdlevel is "percent", it runs normally, and when it's a state value (balanced, unbalanced, over-balanced), it goes wrong! If there is a problem with the SQL statement, put the above SQL statement parameters into, run in PL/sql, everything is OK! If there is a problem with the P_phdlevel parameter, the P_company parameter has no problem! Two parameters are the same string type! Continue to ponder ... p_company parameter no problem, that is to say, B.company =:p _company This condition is not a problem, that is, the data types on both sides of the equals sign are consistent! P_phdlevel There is a problem, that is to say, a.phdlevel like:p _phdlevel This condition is problematic, and from the error message, this condition exists unreasonable type conversion (unreasonable conversion)! B.company is a field in the Entity table, and the type Varchar2,p_company parameter is also the VARCHAR2 (ORACLEDBTYPE.VARCHAR2) type! A.phdlvel is not a field of an entity table, but a field generated by a SELECT statement, what type is it? The type of the P_phdlevel parameter is VARCHAR2 (ORACLDBTYPE.VARCHAR2)! In this case, the A.phdlevel parameter must not be VARCHAR2 type! Nor is the NVARCHAR2 type (after the P_phdlevel parameter type is changed to the NVARCHAR2 type, the error is normal)! Is it a Char type? Change the P_phdlevel parameter type to Char:
Normal operation!
At this point, the problem is resolved, but it does not eliminate the bizarre Oracle: If the type of a.phdlevel is Char, causing an error because the P_phdlevel parameter is of type error (VARCHAR2), why is the P_phdlevel value " Often, and when the value is Chinese ("unbalanced") it goes wrong?
The possible explanations are:
Conditions a.phdlevel like:p _phlevel there is a type conversion: Convert the P_phdlevel parameter of the VARCHAR2 type to Char type, which can be converted normally when the P_phdlevel value is "percent", and when P_phd When the level value is Chinese, it cannot be converted! If so, it is even more incredible. Char is a fixed-length string type, and VARCHAR2 is a variable-length string type, and there is no essential difference between them! Clumsy and bizarre oracle!.
Clumsy and bizarre Oracle
