HPCC-13874 Improve mySQL error messages

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>

plugins/mysql/mysqlembed.cpp

@@ -231,10 +231,15 @@ public:
     {
         return columns;
     }
-    inline MYSQL_BIND &queryColumn(int colIdx) const
+    inline MYSQL_BIND &queryColumn(int colIdx, const char *name) const
     {
         if (colIdx >= columns)
-            fail("Column index out of range");
+        {
+            VStringBuffer error("No matching bound column for parameter %d", colIdx);
+            if (name)
+                error.appendf(" (%s)", name);
+            fail(error);
+        }
         return bindinfo[colIdx];
     }
     inline MYSQL_BIND *queryBindings() const
@@ -691,7 +696,7 @@ protected:
             colIdx++;
         else
             fail("Too many fields in ECL output row");
-        const MYSQL_BIND &column = resultInfo.queryColumn(colIdx);
+        const MYSQL_BIND &column = resultInfo.queryColumn(colIdx,field->name->queryStr());
         if (*column.error)
             failx("Error fetching column %s", field->name->queryStr());
         return column;
@@ -846,7 +851,7 @@ public:
 protected:
     MYSQL_BIND &createBindBuffer(enum_field_types sqlType, unsigned size)
     {
-        MYSQL_BIND &bindInfo = bindings.queryColumn(thisParam++);
+        MYSQL_BIND &bindInfo = bindings.queryColumn(thisParam++, NULL);
         mysqlembed::createBindBuffer(bindInfo, sqlType, size);
         return bindInfo;
     }
@@ -1198,7 +1203,7 @@ public:
     virtual void callFunction()
     {
         if (nextParam != stmtInfo->queryInputBindings().numColumns())
-            fail("Not enough parameters");
+            failx("Not enough parameters supplied (%d parameters supplied, but statement has %d bound columns)", nextParam, stmtInfo->queryInputBindings().numColumns());
         if (!stmtInfo->hasResult())
             lazyExecute();
     }
@@ -1217,7 +1222,7 @@ protected:
         lazyExecute(); // MORE this seems wrong to me  - or at least needs to check not already executed
         if (!stmtInfo->next())
             typeError("scalar", NULL);
-        return stmtInfo->queryResultBindings().queryColumn(0);
+        return stmtInfo->queryResultBindings().queryColumn(0, NULL);
     }
     void checkSingleRow()
     {
@@ -1227,7 +1232,7 @@ protected:
     inline MYSQL_BIND &findParameter(const char *name, enum_field_types sqlType, unsigned size)
     {
         // Everything is positional in MySQL
-        MYSQL_BIND &bindInfo = stmtInfo->queryInputBindings().queryColumn(nextParam++);
+        MYSQL_BIND &bindInfo = stmtInfo->queryInputBindings().queryColumn(nextParam++, name);
         createBindBuffer(bindInfo, sqlType, size);
         return bindInfo;
     }