Do not convert standard TRIM function to non-standard functions

h2/src/docsrc/help/help.csv

@@ -4509,7 +4509,7 @@ RTRIM(NAME)
 "
 
 "Functions (String)","TRIM","
-TRIM ( [ { LEADING | TRAILING | BOTH } [ string ] FROM ] string )
+TRIM ( [ [ LEADING | TRAILING | BOTH ] [ string ] FROM ] string )
 ","
 Removes all leading spaces, trailing spaces, or spaces at both ends, from a string.
 Other characters can be removed as well.

h2/src/main/org/h2/command/Parser.java

@@ -3582,32 +3582,40 @@ public class Parser {
             break;
         }
         case Function.TRIM: {
-            Expression space = null;
+            int flags;
+            boolean needFrom = false;
             if (readIf("LEADING")) {
-                function = Function.getFunction(database, "LTRIM");
-                if (!readIf(FROM)) {
-                    space = readExpression();
-                    read(FROM);
-                }
+                flags = Function.TRIM_LEADING;
+                needFrom = true;
             } else if (readIf("TRAILING")) {
-                function = Function.getFunction(database, "RTRIM");
-                if (!readIf(FROM)) {
-                    space = readExpression();
-                    read(FROM);
+                flags = Function.TRIM_TRAILING;
+                needFrom = true;
+            } else {
+                needFrom = readIf("BOTH");
+                flags = Function.TRIM_LEADING | Function.TRIM_TRAILING;
             }
-            } else if (readIf("BOTH")) {
+            Expression p0, space = null;
+            function.setFlags(flags);
+            if (needFrom) {
                 if (!readIf(FROM)) {
                     space = readExpression();
                     read(FROM);
                 }
-            }
-            Expression p0 = readExpression();
-            if (readIf(COMMA)) {
-                space = readExpression();
-            } else if (readIf(FROM)) {
+                p0 = readExpression();
+            } else {
+                if (readIf(FROM)) {
+                    p0 = readExpression();
+                } else {
+                    p0 = readExpression();
+                    if (readIf(FROM)) {
                         space = p0;
                         p0 = readExpression();
                     }
+                }
+            }
+            if (!needFrom && space == null && readIf(COMMA)) {
+                space = readExpression();
+            }
             function.setParameter(0, p0);
             if (space != null) {
                 function.setParameter(1, space);

h2/src/main/org/h2/expression/function/Function.java

@@ -153,6 +153,16 @@ public class Function extends Expression implements FunctionCall {
      */
     public static final int H2VERSION = 231;
 
+    /**
+     * The flags for TRIM(LEADING ...) function.
+     */
+    public static final int TRIM_LEADING = 1;
+
+    /**
+     * The flags for TRIM(TRAILING ...) function.
+     */
+    public static final int TRIM_TRAILING = 2;
+
     protected static final int VAR_ARGS = -1;
 
     private static final HashMap<String, FunctionInfo> FUNCTIONS = new HashMap<>(256);
@@ -162,6 +172,7 @@ public class Function extends Expression implements FunctionCall {
 
     protected final FunctionInfo info;
     private ArrayList<Expression> varArgs;
+    private int flags;
     protected TypeInfo type;
 
     private final Database database;
@@ -573,6 +584,24 @@ public class Function extends Expression implements FunctionCall {
         }
     }
 
+    /**
+     * Set the flags for this function.
+     *
+     * @param flags the flags to set
+     */
+    public void setFlags(int flags) {
+        this.flags = flags;
+    }
+
+    /**
+     * Returns the flags.
+     *
+     * @return the flags
+     */
+    public int getFlags() {
+        return flags;
+    }
+
     @Override
     public Value getValue(Session session) {
         return getValueWithArgs(session, args);
@@ -1343,7 +1372,7 @@ public class Function extends Expression implements FunctionCall {
             break;
         case TRIM:
             result = ValueString.get(StringUtils.trim(v0.getString(),
-                    true, true, v1 == null ? " " : v1.getString()),
+                    (flags & TRIM_LEADING) != 0, (flags & TRIM_TRAILING) != 0, v1 == null ? " " : v1.getString()),
                     database.getMode().treatEmptyStringsAsNull);
             break;
         case RTRIM:
@@ -2602,6 +2631,21 @@ public class Function extends Expression implements FunctionCall {
             builder.append('(');
         }
         switch (info.type) {
+        case TRIM: {
+            switch (flags) {
+            case TRIM_LEADING:
+                builder.append("LEADING ");
+                break;
+            case TRIM_TRAILING:
+                builder.append("TRAILING ");
+                break;
+            }
+            if (args.length > 1) {
+                args[1].getSQL(builder, alwaysQuote).append(" FROM ");
+            }
+            args[0].getSQL(builder, alwaysQuote);
+            break;
+        }
         case CAST: {
             args[0].getSQL(builder, alwaysQuote).append(" AS ").append(new Column(null, type).getCreateSQL());
             break;

h2/src/test/org/h2/test/scripts/functions/string/trim.sql

@@ -3,14 +3,23 @@
 -- Initial Developer: H2 Group
 --
 
-create memory table test(id int primary key, name varchar(255));
+CREATE TABLE TEST(ID INT PRIMARY KEY, A VARCHAR, B VARCHAR, C VARCHAR) AS VALUES (1, '__A__', '    B    ', 'xAx');
 > ok
 
-insert into test values(1, 'Hello');
-> update count: 1
+SELECT TRIM(BOTH '_' FROM A), '|' || TRIM(LEADING FROM B) || '|', TRIM(TRAILING 'x' FROM C) FROM TEST;
+> TRIM('_' FROM A) ('|' || TRIM(LEADING B)) || '|' TRIM(TRAILING 'x' FROM C)
+> ---------------- ------------------------------- -------------------------
+> A                |B |                            xA
+> rows: 1
 
-select TRIM(BOTH '_' FROM '__A__') A, TRIM(LEADING FROM '    B    ') BS, TRIM(TRAILING 'x' FROM 'xAx') XA from test;
-> A BS XA
-> - -- --
-> A B  xA
+SELECT LENGTH(TRIM(B)), LENGTH(TRIM(FROM B)) FROM TEST;
+> LENGTH(TRIM(B)) LENGTH(TRIM(B))
+> --------------- ---------------
+> 1               1
 > rows: 1
+
+SELECT TRIM(BOTH B) FROM TEST;
+> exception SYNTAX_ERROR_2
+
+DROP TABLE TEST;
+> ok