From 61c18a6c5b29f8cc192cf26477d621e0dd8557d9 Mon Sep 17 00:00:00 2001
From: 924060929 <lanhuajian@selectdb.com>
Date: Fri, 20 Dec 2024 22:03:37 +0800
Subject: [PATCH] optimize

---
 .../doris/nereids/parser/NereidsParser.java   | 32 +++++++++++++++++++
 .../org/apache/doris/nereids/util/Utils.java  | 12 +++++--
 2 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/parser/NereidsParser.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/parser/NereidsParser.java
index 34646c1d6579534..4890ddd214d5ae9 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/parser/NereidsParser.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/parser/NereidsParser.java
@@ -24,6 +24,7 @@
 import org.apache.doris.nereids.DorisLexer;
 import org.apache.doris.nereids.DorisParser;
 import org.apache.doris.nereids.StatementContext;
+import org.apache.doris.nereids.analyzer.UnboundSlot;
 import org.apache.doris.nereids.glue.LogicalPlanAdapter;
 import org.apache.doris.nereids.parser.plsql.PLSqlLogicalPlanBuilder;
 import org.apache.doris.nereids.trees.expressions.Expression;
@@ -35,6 +36,7 @@
 import org.apache.doris.qe.ConnectContext;
 import org.apache.doris.qe.SessionVariable;
 
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import org.antlr.v4.runtime.CharStreams;
@@ -66,6 +68,8 @@ public class NereidsParser {
 
     private static final BitSet EXPLAIN_TOKENS = new BitSet();
 
+    private static final Map<String, Integer> LITERAL_TOKENS;
+
     static {
         EXPLAIN_TOKENS.set(DorisLexer.EXPLAIN);
         EXPLAIN_TOKENS.set(DorisLexer.PARSED);
@@ -77,6 +81,14 @@ public class NereidsParser {
         EXPLAIN_TOKENS.set(DorisLexer.PLAN);
         EXPLAIN_TOKENS.set(DorisLexer.PROCESS);
 
+        ImmutableMap.Builder<String, Integer> literalToTokenType = ImmutableMap.builder();
+        for (int tokenType = 0; tokenType <= DorisLexer.VOCABULARY.getMaxTokenType(); tokenType++) {
+            String literalName = DorisLexer.VOCABULARY.getLiteralName(tokenType);
+            if (literalName != null) {
+                literalToTokenType.put(literalName.substring(1, literalName.length() - 1), tokenType);
+            }
+        }
+        LITERAL_TOKENS = literalToTokenType.build();
     }
 
     /**
@@ -256,9 +268,29 @@ public List<Pair<LogicalPlan, StatementContext>> parseMultiple(String sql,
     }
 
     public Expression parseExpression(String expression) {
+        if (isSimpleIdentifier(expression)) {
+            return new UnboundSlot(expression);
+        }
         return parse(expression, DorisParser::expression);
     }
 
+    private boolean isSimpleIdentifier(String expression) {
+        if (expression == null || expression.isEmpty()) {
+            return false;
+        }
+
+        boolean hasLetter = false;
+        for (int i = 0; i < expression.length(); i++) {
+            char c = expression.charAt(i);
+            if ((('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') || c == '_' || c == '$')) {
+                hasLetter = true;
+            } else if (!('0' <= c && c <= '9')) {
+                return false;
+            }
+        }
+        return hasLetter && !LITERAL_TOKENS.containsKey(expression.toUpperCase());
+    }
+
     public DataType parseDataType(String dataType) {
         return parse(dataType, DorisParser::dataType);
     }
diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/util/Utils.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/util/Utils.java
index 42b99f6effdb842..c111839fc5093ec 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/util/Utils.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/util/Utils.java
@@ -58,8 +58,16 @@ public class Utils {
      */
     public static String quoteIfNeeded(String part) {
         // We quote strings except the ones which consist of digits only.
-        return part.matches("\\w*[\\w&&[^\\d]]+\\w*")
-                ? part : part.replace("`", "``");
+        StringBuilder quote = new StringBuilder(part.length());
+        for (int i = 0; i < part.length(); i++) {
+            char c = part.charAt(i);
+            if (c == '`') {
+                quote.append("``");
+            } else {
+                quote.append(c);
+            }
+        }
+        return quote.toString();
     }
 
     /**