Revert "added undeclared variable error message"

This reverts commit 11bccd6.

Author: angelamayxie

sql/errors.go

@@ -238,9 +238,6 @@ var (
 	// ErrEventDoesNotExist is returned when an event does not exist.
 	ErrEventDoesNotExist = errors.NewKind("Event '%s' does not exist")
 
-	// ErrUndeclaredVariable is return when an undeclared variable is used.
-	ErrUndeclaredVariable = errors.NewKind("Undeclared variable: '%s'")
-
 	// ErrUnknownEvent is returned when a query references an event that doesn't exist
 	ErrUnknownEvent = errors.NewKind("Unknown event '%s'")
 

sql/planbuilder/dml.go

@@ -752,7 +752,7 @@ func (b *Builder) buildInto(inScope *scope, into *ast.Into) {
 			vars[i] = expression.NewUserVar(strings.TrimPrefix(val.String(), "@"))
 		} else {
 			if inScope.proc == nil {
-				err := sql.ErrUndeclaredVariable.New(val.String())
+				err := sql.ErrExternalProcedureMissingContextParam.New(val.String())
 				b.handleErr(err)
 			}
 			col, ok := inScope.proc.GetVar(val.String())