Generate only standard OFFSET / FETCH in Query.appendLimitToSQL()

h2/src/main/org/h2/command/dml/Query.java

@@ -691,25 +691,22 @@ public abstract class Query extends Prepared {
     }
 
     void appendLimitToSQL(StringBuilder buff) {
+        if (offsetExpr != null) {
+            String count = StringUtils.unEnclose(offsetExpr.getSQL());
+            buff.append("\nOFFSET ").append(count).append("1".equals(count) ? " ROW" : " ROWS");
+        }
         if (limitExpr != null) {
-            if (fetchPercent || withTies) {
-                if (offsetExpr != null) {
-                    buff.append("\nOFFSET ").append(StringUtils.unEnclose(offsetExpr.getSQL())).append(" ROWS");
-                }
-                buff.append("\nFETCH NEXT ").append(StringUtils.unEnclose(limitExpr.getSQL()));
+            buff.append("\nFETCH ").append(offsetExpr != null ? "NEXT" : "FIRST");
+            String count = StringUtils.unEnclose(limitExpr.getSQL());
+            boolean withCount = fetchPercent || !"1".equals(count);
+            if (withCount) {
+                buff.append(' ').append(count);
                 if (fetchPercent) {
                     buff.append(" PERCENT");
                 }
-                buff.append(" ROWS");
-                if (withTies) {
-                    buff.append(" WITH TIES");
-                }
-            } else {
-                buff.append("\nLIMIT ").append(StringUtils.unEnclose(limitExpr.getSQL()));
-                if (offsetExpr != null) {
-                    buff.append("\nOFFSET ").append(StringUtils.unEnclose(offsetExpr.getSQL()));
-                }
             }
+            buff.append(!withCount ? " ROW" : " ROWS")
+                    .append(withTies ? " WITH TIES" : " ONLY");
         }
     }
 

h2/src/test/org/h2/samples/optimizations.sql

@@ -62,7 +62,7 @@ EXPLAIN SELECT DISTINCT TYPE FROM TEST ORDER BY TYPE LIMIT 3;
 -->    FROM PUBLIC.TEST
 -->        /* PUBLIC.IDX_TEST_TYPE */
 -->    ORDER BY 1
--->    LIMIT 3
+-->    FETCH FIRST 3 ROWS ONLY
 -->    /* distinct */
 -->    /* index sorted */
 ;
@@ -144,7 +144,7 @@ FROM (SELECT DISTINCT TYPE FROM TEST) T ORDER BY TYPE;
 -->            /* PUBLIC.IDX_TEST_TYPE_VALUE: TYPE = T.TYPE */
 -->        WHERE T.TYPE = T2.TYPE
 -->        ORDER BY =TYPE, 1
--->        LIMIT 1
+-->        FETCH FIRST ROW ONLY
 -->        /* index sorted */) AS MIN
 -->    FROM (
 -->        SELECT DISTINCT
@@ -194,7 +194,7 @@ EXPLAIN SELECT VALUE FROM TEST ORDER BY VALUE LIMIT 10;
 -->    FROM PUBLIC.TEST
 -->        /* PUBLIC.IDX_TEST_VALUE */
 -->    ORDER BY 1
--->    LIMIT 10
+-->    FETCH FIRST 10 ROWS ONLY
 -->    /* index sorted */
 ;
 
@@ -215,7 +215,7 @@ EXPLAIN SELECT VALUE FROM TEST ORDER BY VALUE DESC LIMIT 10;
 -->    FROM PUBLIC.TEST
 -->        /* PUBLIC.IDX_TEST_VALUE_D */
 -->    ORDER BY 1 DESC
--->    LIMIT 10
+-->    FETCH FIRST 10 ROWS ONLY
 -->    /* index sorted */
 ;
 

h2/src/test/org/h2/test/scripts/dml/select.sql

@@ -213,7 +213,7 @@ SELECT * FROM TEST FETCH FIRST 1 ROW WITH TIES;
 > exception WITH_TIES_WITHOUT_ORDER_BY
 
 EXPLAIN SELECT * FROM TEST ORDER BY A, B OFFSET 3 ROWS FETCH NEXT 1 ROW WITH TIES;
->> SELECT TEST.A, TEST.B, TEST.C FROM PUBLIC.TEST /* PUBLIC.TEST_A_B_IDX */ ORDER BY 1, 2 OFFSET 3 ROWS FETCH NEXT 1 ROWS WITH TIES /* index sorted */
+>> SELECT TEST.A, TEST.B, TEST.C FROM PUBLIC.TEST /* PUBLIC.TEST_A_B_IDX */ ORDER BY 1, 2 OFFSET 3 ROWS FETCH NEXT ROW WITH TIES /* index sorted */
 
 EXPLAIN SELECT * FROM TEST ORDER BY A, B OFFSET 3 ROWS FETCH NEXT 1 PERCENT ROWS WITH TIES;
 >> SELECT TEST.A, TEST.B, TEST.C FROM PUBLIC.TEST /* PUBLIC.TEST_A_B_IDX */ ORDER BY 1, 2 OFFSET 3 ROWS FETCH NEXT 1 PERCENT ROWS WITH TIES /* index sorted */

h2/src/test/org/h2/test/scripts/testScript.sql

@@ -484,8 +484,8 @@ explain insert into test(id) direct sorted select x from system_range(1, 100);
 >> INSERT INTO PUBLIC.TEST(ID) DIRECT SORTED SELECT X FROM SYSTEM_RANGE(1, 100) /* PUBLIC.RANGE_INDEX */
 
 explain select * from test limit 10 sample_size 10;
-#+mvStore#>> SELECT TEST.ID FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */ LIMIT 10 SAMPLE_SIZE 10
-#-mvStore#>> SELECT TEST.ID FROM PUBLIC.TEST /* PUBLIC.PRIMARY_KEY_2 */ LIMIT 10 SAMPLE_SIZE 10
+#+mvStore#>> SELECT TEST.ID FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */ FETCH FIRST 10 ROWS ONLY SAMPLE_SIZE 10
+#-mvStore#>> SELECT TEST.ID FROM PUBLIC.TEST /* PUBLIC.PRIMARY_KEY_2 */ FETCH FIRST 10 ROWS ONLY SAMPLE_SIZE 10
 
 drop table test;
 > ok
@@ -4991,7 +4991,7 @@ SELECT LIMIT (1+0) (2+0) NAME, -ID, ID _ID_ FROM TEST ORDER BY _ID_;
 > rows (ordered): 2
 
 EXPLAIN SELECT LIMIT (1+0) (2+0) * FROM TEST ORDER BY ID;
->> SELECT TEST.ID, TEST.NAME FROM PUBLIC.TEST /* PUBLIC.PRIMARY_KEY_2 */ ORDER BY 1 LIMIT 2 OFFSET 1 /* index sorted */
+>> SELECT TEST.ID, TEST.NAME FROM PUBLIC.TEST /* PUBLIC.PRIMARY_KEY_2 */ ORDER BY 1 OFFSET 1 ROW FETCH NEXT 2 ROWS ONLY /* index sorted */
 
 SELECT * FROM TEST ORDER BY ID LIMIT 2+0 OFFSET 1+0;
 > ID NAME
@@ -5039,7 +5039,7 @@ SELECT * FROM (SELECT ID FROM TEST GROUP BY ID);
 > rows: 5
 
 EXPLAIN SELECT * FROM TEST UNION ALL SELECT * FROM TEST ORDER BY ID LIMIT 2+0 OFFSET 1+0;
->> (SELECT TEST.ID, TEST.NAME FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */) UNION ALL (SELECT TEST.ID, TEST.NAME FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */) ORDER BY 1 LIMIT 2 OFFSET 1
+>> (SELECT TEST.ID, TEST.NAME FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */) UNION ALL (SELECT TEST.ID, TEST.NAME FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */) ORDER BY 1 OFFSET 1 ROW FETCH NEXT 2 ROWS ONLY
 
 EXPLAIN DELETE FROM TEST WHERE ID=1;
 >> DELETE FROM PUBLIC.TEST /* PUBLIC.PRIMARY_KEY_2: ID = 1 */ WHERE ID = 1
@@ -5223,7 +5223,7 @@ EXPLAIN SELECT * FROM TEST WHERE 1=0;
 >> SELECT TEST.ID, TEST.NAME FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan: FALSE */ WHERE FALSE
 
 EXPLAIN SELECT TOP 1 * FROM TEST FOR UPDATE;
->> SELECT TEST.ID, TEST.NAME FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */ LIMIT 1 FOR UPDATE
+>> SELECT TEST.ID, TEST.NAME FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */ FETCH FIRST ROW ONLY FOR UPDATE
 
 EXPLAIN SELECT COUNT(NAME) FROM TEST WHERE ID=1;
 >> SELECT COUNT(NAME) FROM PUBLIC.TEST /* PUBLIC.PRIMARY_KEY_2: ID = 1 */ WHERE ID = 1