Support both standard and StarRocks LIMIT/OFFSET syntax in SQL parser

Co-authored-by: huanmingwong <huanmingwong@gmail.com>

fe/fe-core/src/main/java/com/starrocks/sql/parser/AstBuilder.java

@@ -5974,15 +5974,17 @@ public class AstBuilder extends StarRocksBaseVisitor<ParseNode> {
         Expr limit;
         Expr offset = new IntLiteral(0);
 
-        if (context.limit.INTEGER_VALUE() != null) {
-            limit = new IntLiteral(Long.parseLong(context.limit.INTEGER_VALUE().getText()));
-        } else if (context.limit.userVariable() != null) {
-            limit = (UserVariableExpr) visit(context.limit.userVariable());
-        } else {
-            throw new ParsingException("unsupported invalid limit value", createPos(context.limit));
+        // Check if this is the comma-separated syntax: LIMIT offset, limit
+        boolean isCommaSyntax = false;
+        for (int i = 0; i < context.getChildCount(); ++i) {
+            if (context.getChild(i).getText().equals(",")) {
+                isCommaSyntax = true;
+                break;
+            }
         }
 
-        if (context.offset != null) {
+        if (isCommaSyntax) {
+            // Handle LIMIT offset, limit syntax (current StarRocks style)
             if (context.offset.INTEGER_VALUE() != null) {
                 offset = new IntLiteral(Long.parseLong(context.offset.INTEGER_VALUE().getText()));
             } else if (context.offset.userVariable() != null) {
@@ -5990,7 +5992,35 @@ public class AstBuilder extends StarRocksBaseVisitor<ParseNode> {
             } else {
                 throw new ParsingException("unsupported invalid offset value", createPos(context.offset));
             }
+
+            if (context.limit.INTEGER_VALUE() != null) {
+                limit = new IntLiteral(Long.parseLong(context.limit.INTEGER_VALUE().getText()));
+            } else if (context.limit.userVariable() != null) {
+                limit = (UserVariableExpr) visit(context.limit.userVariable());
+            } else {
+                throw new ParsingException("unsupported invalid limit value", createPos(context.limit));
+            }
+        } else {
+            // Handle LIMIT limit [OFFSET offset] syntax (standard SQL style)
+            if (context.limit.INTEGER_VALUE() != null) {
+                limit = new IntLiteral(Long.parseLong(context.limit.INTEGER_VALUE().getText()));
+            } else if (context.limit.userVariable() != null) {
+                limit = (UserVariableExpr) visit(context.limit.userVariable());
+            } else {
+                throw new ParsingException("unsupported invalid limit value", createPos(context.limit));
+            }
+
+            if (context.offset != null) {
+                if (context.offset.INTEGER_VALUE() != null) {
+                    offset = new IntLiteral(Long.parseLong(context.offset.INTEGER_VALUE().getText()));
+                } else if (context.offset.userVariable() != null) {
+                    offset = (UserVariableExpr) visit(context.offset.userVariable());
+                } else {
+                    throw new ParsingException("unsupported invalid offset value", createPos(context.offset));
+                }
+            }
         }
+        
         return new LimitElement(offset, limit, createPos(context));
     }
 

test/sql/test_limit_offset_syntax/R/test_limit_offset_edge_cases

@@ -0,0 +1,67 @@
+-- name: test_limit_offset_edge_cases
+CREATE DATABASE db_${uuid0};
+-- result:
+-- !result
+USE db_${uuid0};
+-- result:
+-- !result
+CREATE TABLE test_table (
+    id INT,
+    value VARCHAR(50)
+) DUPLICATE KEY(id)
+DISTRIBUTED BY HASH(id) BUCKETS 1;
+-- result:
+-- !result
+INSERT INTO test_table VALUES 
+(1, 'a'), (2, 'b'), (3, 'c'), (4, 'd'), (5, 'e');
+-- result:
+-- !result
+SET @my_limit = 2;
+-- result:
+-- !result
+SET @my_offset = 1;
+-- result:
+-- !result
+SELECT id, value FROM test_table ORDER BY id LIMIT @my_limit OFFSET @my_offset;
+-- result:
+2	b
+3	c
+-- !result
+SELECT id, value FROM test_table ORDER BY id LIMIT @my_offset, @my_limit;
+-- result:
+2	b
+3	c
+-- !result
+SELECT id, value FROM test_table ORDER BY id LIMIT 3 OFFSET @my_offset;
+-- result:
+2	b
+3	c
+4	d
+-- !result
+SELECT id, value FROM test_table ORDER BY id LIMIT @my_limit OFFSET 3;
+-- result:
+4	d
+5	e
+-- !result
+SELECT id, value FROM test_table ORDER BY id LIMIT 2 OFFSET 0;
+-- result:
+1	a
+2	b
+-- !result
+SELECT id, value FROM test_table ORDER BY id LIMIT 0, 2;
+-- result:
+1	a
+2	b
+-- !result
+SELECT id, value FROM test_table ORDER BY id LIMIT 2 OFFSET 10;
+-- result:
+-- !result
+SELECT id, value FROM test_table ORDER BY id LIMIT 10, 2;
+-- result:
+-- !result
+DROP TABLE test_table;
+-- result:
+-- !result
+DROP DATABASE db_${uuid0};
+-- result:
+-- !result

test/sql/test_limit_offset_syntax/R/test_limit_offset_syntax

@@ -0,0 +1,76 @@
+-- name: test_limit_offset_syntax
+CREATE DATABASE db_${uuid0};
+-- result:
+-- !result
+USE db_${uuid0};
+-- result:
+-- !result
+CREATE TABLE test_table (
+    id INT,
+    name VARCHAR(50)
+) DUPLICATE KEY(id)
+DISTRIBUTED BY HASH(id) BUCKETS 1;
+-- result:
+-- !result
+INSERT INTO test_table VALUES 
+(1, 'row1'),
+(2, 'row2'), 
+(3, 'row3'),
+(4, 'row4'),
+(5, 'row5'),
+(6, 'row6'),
+(7, 'row7'),
+(8, 'row8'),
+(9, 'row9'),
+(10, 'row10');
+-- result:
+-- !result
+SELECT id, name FROM test_table ORDER BY id LIMIT 3 OFFSET 2;
+-- result:
+3	row3
+4	row4
+5	row5
+-- !result
+SELECT id, name FROM test_table ORDER BY id LIMIT 2, 3;
+-- result:
+3	row3
+4	row4
+5	row5
+-- !result
+SELECT id, name FROM test_table ORDER BY id LIMIT 2;
+-- result:
+1	row1
+2	row2
+-- !result
+SELECT id, name FROM test_table ORDER BY id LIMIT 3 OFFSET 0;
+-- result:
+1	row1
+2	row2
+3	row3
+-- !result
+SELECT id, name FROM test_table ORDER BY id LIMIT 3 OFFSET 7;
+-- result:
+8	row8
+9	row9
+10	row10
+-- !result
+SELECT id, name FROM test_table ORDER BY id LIMIT 7, 3;
+-- result:
+8	row8
+9	row9
+10	row10
+-- !result
+SELECT id, name FROM test_table ORDER BY id LIMIT 1 OFFSET 9;
+-- result:
+10	row10
+-- !result
+SELECT id, name FROM test_table ORDER BY id LIMIT 9, 1;
+-- result:
+10	row10
+-- !result
+DROP TABLE test_table;
+-- result:
+-- !result
+DROP DATABASE db_${uuid0};
+-- result:
+-- !result

test/sql/test_limit_offset_syntax/T/test_limit_offset_edge_cases

@@ -0,0 +1,48 @@
+-- name: test_limit_offset_edge_cases
+-- Test edge cases for LIMIT OFFSET syntax
+
+CREATE DATABASE db_${uuid0};
+USE db_${uuid0};
+
+-- Create test table
+CREATE TABLE test_table (
+    id INT,
+    value VARCHAR(50)
+) DUPLICATE KEY(id)
+DISTRIBUTED BY HASH(id) BUCKETS 1;
+
+-- Insert test data
+INSERT INTO test_table VALUES 
+(1, 'a'), (2, 'b'), (3, 'c'), (4, 'd'), (5, 'e');
+
+-- Test with user variables
+SET @my_limit = 2;
+SET @my_offset = 1;
+
+-- Test 1: Standard syntax with user variables
+SELECT id, value FROM test_table ORDER BY id LIMIT @my_limit OFFSET @my_offset;
+
+-- Test 2: StarRocks syntax with user variables
+SELECT id, value FROM test_table ORDER BY id LIMIT @my_offset, @my_limit;
+
+-- Test 3: Mixed - literal limit, variable offset
+SELECT id, value FROM test_table ORDER BY id LIMIT 3 OFFSET @my_offset;
+
+-- Test 4: Mixed - variable limit, literal offset  
+SELECT id, value FROM test_table ORDER BY id LIMIT @my_limit OFFSET 3;
+
+-- Test 5: Zero offset (standard syntax)
+SELECT id, value FROM test_table ORDER BY id LIMIT 2 OFFSET 0;
+
+-- Test 6: Zero offset (StarRocks syntax)
+SELECT id, value FROM test_table ORDER BY id LIMIT 0, 2;
+
+-- Test 7: Large offset that exceeds table size
+SELECT id, value FROM test_table ORDER BY id LIMIT 2 OFFSET 10;
+
+-- Test 8: Large offset that exceeds table size (StarRocks syntax)
+SELECT id, value FROM test_table ORDER BY id LIMIT 10, 2;
+
+-- Clean up
+DROP TABLE test_table;
+DROP DATABASE db_${uuid0};

test/sql/test_limit_offset_syntax/T/test_limit_offset_syntax

@@ -0,0 +1,62 @@
+-- name: test_limit_offset_syntax
+-- Test both LIMIT syntaxes to ensure they work correctly after the fix
+
+-- Create test database
+CREATE DATABASE db_${uuid0};
+USE db_${uuid0};
+
+-- Create test table
+CREATE TABLE test_table (
+    id INT,
+    name VARCHAR(50)
+) DUPLICATE KEY(id)
+DISTRIBUTED BY HASH(id) BUCKETS 1;
+
+-- Insert test data
+INSERT INTO test_table VALUES 
+(1, 'row1'),
+(2, 'row2'), 
+(3, 'row3'),
+(4, 'row4'),
+(5, 'row5'),
+(6, 'row6'),
+(7, 'row7'),
+(8, 'row8'),
+(9, 'row9'),
+(10, 'row10');
+
+-- Test 1: Standard SQL syntax - LIMIT count OFFSET offset
+-- Should return rows with id 3, 4, 5 (3 rows starting from offset 2)
+SELECT id, name FROM test_table ORDER BY id LIMIT 3 OFFSET 2;
+
+-- Test 2: StarRocks syntax - LIMIT offset, count  
+-- Should return the same rows with id 3, 4, 5
+SELECT id, name FROM test_table ORDER BY id LIMIT 2, 3;
+
+-- Test 3: LIMIT without OFFSET (standard syntax)
+-- Should return first 2 rows
+SELECT id, name FROM test_table ORDER BY id LIMIT 2;
+
+-- Test 4: LIMIT with OFFSET 0 (standard syntax)  
+-- Should return first 3 rows
+SELECT id, name FROM test_table ORDER BY id LIMIT 3 OFFSET 0;
+
+-- Test 5: Large offset (standard syntax)
+-- Should return rows 8, 9, 10
+SELECT id, name FROM test_table ORDER BY id LIMIT 3 OFFSET 7;
+
+-- Test 6: Large offset (StarRocks syntax)
+-- Should return the same rows 8, 9, 10
+SELECT id, name FROM test_table ORDER BY id LIMIT 7, 3;
+
+-- Test 7: Edge case - LIMIT 1 OFFSET 9
+-- Should return only row 10
+SELECT id, name FROM test_table ORDER BY id LIMIT 1 OFFSET 9;
+
+-- Test 8: Edge case - LIMIT 9, 1 (equivalent to above)
+-- Should return only row 10
+SELECT id, name FROM test_table ORDER BY id LIMIT 9, 1;
+
+-- Clean up
+DROP TABLE test_table;
+DROP DATABASE db_${uuid0};