fix for name resolution collision bug (dolt#1661)

Author: andy-wm-arthur

sql/analyzer/resolve_orderby.go

@@ -41,9 +41,12 @@ func pushdownSort(ctx *sql.Context, a *Analyzer, n sql.Node, scope *Scope) (sql.
 		}
 
 		childAliases := aliasesDefinedInNode(sort.Child)
-		var schemaCols []string
+		var schemaCols []tableCol
 		for _, col := range sort.Child.Schema() {
-			schemaCols = append(schemaCols, strings.ToLower(col.Name))
+			schemaCols = append(schemaCols, tableCol{
+				table: strings.ToLower(col.Source),
+				col: strings.ToLower(col.Name),
+			})
 		}
 
 		var colsFromChild []string
@@ -55,7 +58,7 @@ func pushdownSort(ctx *sql.Context, a *Analyzer, n sql.Node, scope *Scope) (sql.
 				name := strings.ToLower(n.Name())
 				if stringContains(childAliases, name) {
 					colsFromChild = append(colsFromChild, n.Name())
-				} else if !stringContains(schemaCols, name) {
+				} else if !tableColsContaints(schemaCols, tableColFromNameable(n)) {
 					missingCols = append(missingCols, n.Name())
 				}
 			}
@@ -296,3 +299,13 @@ func findExprNameables(e sql.Expression) []sql.Nameable {
 	})
 	return result
 }
+
+func tableColFromNameable(n sql.Nameable) (tc tableCol) {
+	tc = tableCol{
+		col: n.Name(),
+	}
+	if t, ok := n.(sql.Tableable); ok {
+		tc.table = t.Table()
+	}
+	return
+}

sql/analyzer/validation_rules.go

@@ -475,3 +475,13 @@ func stringContains(strs []string, target string) bool {
 	}
 	return false
 }
+
+func tableColsContains(strs []tableCol, target tableCol) bool {
+	for _, s := range strs {
+		if s == target {
+			return true
+		}
+	}
+	return false
+}
+