Add support for subqueries.

gk-brown · gk-brown · commit 405131ef674e · 2020-12-20T10:29:54.000-05:00
diff --git a/README.md b/README.md
@@ -798,7 +798,9 @@ String sql = QueryBuilder.select("name", "species", "sex", "birth")
     .where("owner = :owner").toString();
 ```
 
-Insert, update, and delete operations are also supported. In general, string values provided to insert and update statements via the `values()` and `set()` methods are wrapped in single quotes, and any embdedded single quotes are replaced with two successive single quotes. However, any string that starts with ":" or is equal to "?" is assumed to be a parameter reference and is not escaped.    
+Insert, update, and delete operations are also supported. In general, string values provided to the `insertInto()` and `set()` methods are wrapped in single quotes, and any embdedded single quotes are replaced with two successive single quotes. However, any string that starts with ":" or is equal to "?" is assumed to be a parameter reference and is not escaped. 
+
+If an instance of `QueryBuilder` is passed to `insertInto()` or `set()`, it is considered a subquery and wrapped in parentheses.
 
 ## ElementAdapter
 The `ElementAdapter` class provides access to the contents of an XML DOM `Element` via the `Map` interface. The resulting map can then be transformed to another representation via a template document or accessed via a strongly typed interface proxy, as described earlier. 
diff --git a/httprpc-client/src/main/java/org/httprpc/sql/QueryBuilder.java b/httprpc-client/src/main/java/org/httprpc/sql/QueryBuilder.java
@@ -267,7 +267,15 @@ public static QueryBuilder insertInto(String table, Map<String, ?> values) {
                 sqlBuilder.append(", ");
             }
 
-            sqlBuilder.append(encode(values.get(columns.get(i))));
+            Object value = values.get(columns.get(i));
+
+            if (value instanceof QueryBuilder) {
+                sqlBuilder.append("(");
+                sqlBuilder.append(value.toString());
+                sqlBuilder.append(")");
+            } else {
+                sqlBuilder.append(encode(value));
+            }
         }
 
         sqlBuilder.append(")");
@@ -322,7 +330,16 @@ public QueryBuilder set(Map<String, ?> values) {
 
             sqlBuilder.append(entry.getKey());
             sqlBuilder.append(" = ");
-            sqlBuilder.append(encode(entry.getValue()));
+
+            Object value = entry.getValue();
+
+            if (value instanceof QueryBuilder) {
+                sqlBuilder.append("(");
+                sqlBuilder.append(value.toString());
+                sqlBuilder.append(")");
+            } else {
+                sqlBuilder.append(encode(value));
+            }
 
             i++;
         }
@@ -372,7 +389,6 @@ private static String encode(Object value) {
 
                 return stringBuilder.toString();
             }
-
         } else {
             return String.valueOf(value);
         }
diff --git a/httprpc-client/src/test/java/org/httprpc/sql/QueryBuilderTest.java b/httprpc-client/src/test/java/org/httprpc/sql/QueryBuilderTest.java
@@ -50,10 +50,11 @@ public void testInsertInto() {
             entry("b", true),
             entry("c", "hello"),
             entry("d", ":d"),
-            entry("e", "?")
+            entry("e", "?"),
+            entry("f", QueryBuilder.select("f").from("F"))
         )).toString();
 
-        assertEquals("insert into A (a, b, c, d, e) values (1, true, 'hello', :d, ?)", sql);
+        assertEquals("insert into A (a, b, c, d, e, f) values (1, true, 'hello', :d, ?, (select f from F))", sql);
     }
 
     @Test
@@ -63,10 +64,11 @@ public void testUpdate() {
             entry("b", true),
             entry("c", "hello"),
             entry("d", ":d"),
-            entry("e", "?")
+            entry("e", "?"),
+            entry("f", QueryBuilder.select("f").from("F"))
         )).where("a is not null").toString();
 
-        assertEquals("update A set a = 1, b = true, c = 'hello', d = :d, e = ? where a is not null", sql);
+        assertEquals("update A set a = 1, b = true, c = 'hello', d = :d, e = ?, f = (select f from F) where a is not null", sql);
     }
 
     @Test
