feat: model MySQL JSON_TABLE column collations (#2686)

Signed-off-by: minleejae <mmj9808@gmail.com>

Author: minleejae

src/main/java/net/sf/jsqlparser/expression/JsonTableFunction.java

@@ -474,6 +474,7 @@ public static class JsonTableValueColumnDefinition extends JsonTableColumnDefini
         private String columnName;
         private boolean forOrdinality;
         private ColDataType dataType;
+        private String collation;
         private boolean formatJson;
         private boolean exists;
         private boolean onEmptyAfterOnError;
@@ -526,6 +527,16 @@ public JsonTableValueColumnDefinition setDataType(ColDataType dataType) {
             return this;
         }
 
+        /** Returns the column collation, including any identifier quoting, or null if absent. */
+        public String getCollation() {
+            return collation;
+        }
+
+        public JsonTableValueColumnDefinition setCollation(String collation) {
+            this.collation = collation;
+            return this;
+        }
+
         public boolean isFormatJson() {
             return formatJson;
         }
@@ -623,6 +634,9 @@ public String toString() {
             if (dataType != null) {
                 builder.append(" ").append(dataType);
             }
+            if (collation != null) {
+                builder.append(" COLLATE ").append(collation);
+            }
             if (formatJson) {
                 builder.append(" FORMAT JSON");
                 if (encoding != null) {

src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt

@@ -13264,6 +13264,8 @@ JsonTableFunction.JsonTableColumnDefinition JsonTableColumnDefinition() : {
     JsonTableFunction.JsonTableWrapperClause wrapperClause;
     JsonTableFunction.JsonTableQuotesClause quotesClause;
     String encoding;
+    String collation;
+    Token collationLiteral;
 }
 {
     (
@@ -13303,6 +13305,13 @@ JsonTableFunction.JsonTableColumnDefinition JsonTableColumnDefinition() : {
                                 getToken(1).image.equalsIgnoreCase("ALLOW")
                                 || getToken(1).image.equalsIgnoreCase("DISALLOW"))) } )
                 dataType = ColDataType() { valueColumnDefinition.setDataType(dataType); }
+                [ LOOKAHEAD({ Dialect.MYSQL.name().equals(getAsString(Feature.dialect))
+                        && getToken(1).kind == K_COLLATE })
+                    <K_COLLATE>
+                    ( collation = RelObjectName()
+                      | collationLiteral = <S_CHAR_LITERAL> { collation = collationLiteral.image; } )
+                    { valueColumnDefinition.setCollation(collation); }
+                ]
             ]
             [
                 <K_FORMAT> <K_JSON> { valueColumnDefinition.setFormatJson(true); }

src/test/java/net/sf/jsqlparser/expression/JsonTableCollationTest.java

@@ -0,0 +1,86 @@
+/*-
+ * #%L
+ * JSQLParser library
+ * %%
+ * Copyright (C) 2004 - 2026 JSQLParser
+ * %%
+ * Dual licensed under GNU LGPL 2.1 or Apache License 2.0
+ * #L%
+ */
+package net.sf.jsqlparser.expression;
+
+import net.sf.jsqlparser.JSQLParserException;
+import net.sf.jsqlparser.expression.JsonTableFunction.JsonTableValueColumnDefinition;
+import net.sf.jsqlparser.parser.AbstractJSqlParser.Dialect;
+import net.sf.jsqlparser.parser.CCJSqlParserUtil;
+import net.sf.jsqlparser.statement.create.table.ColDataType;
+import net.sf.jsqlparser.statement.select.PlainSelect;
+import net.sf.jsqlparser.statement.select.TableFunction;
+import net.sf.jsqlparser.test.TestUtils;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class JsonTableCollationTest {
+    @ParameterizedTest
+    @ValueSource(strings = {
+            "n VARCHAR(10) COLLATE utf8mb4_bin PATH '$.n'",
+            "n VARCHAR(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin PATH '$.n'",
+            "n VARCHAR(10) COLLATE `utf8mb4_bin` PATH '$.n'",
+            "n VARCHAR(10) COLLATE 'utf8mb4_bin' PATH '$.n'",
+            "n VARCHAR(10) COLLATE \"utf8mb4_bin\" PATH '$.n'",
+            "NESTED PATH '$.items[*]' COLUMNS (n VARCHAR(10) COLLATE utf8mb4_bin PATH '$.n')"
+    })
+    void collatedColumnsRoundTrip(String column) throws JSQLParserException {
+        PlainSelect select = parse(sql(column));
+        parse(select.toString());
+    }
+
+    @Test
+    void collationCanBeInspectedEditedRemovedAndConstructed() throws JSQLParserException {
+        PlainSelect select = parse(sql("n VARCHAR(10) COLLATE utf8mb4_bin PATH '$.n'"));
+        JsonTableFunction table =
+                (JsonTableFunction) ((TableFunction) select.getFromItem()).getFunction();
+        JsonTableValueColumnDefinition column =
+                (JsonTableValueColumnDefinition) table.getColumnsClause().getColumnDefinitions()
+                        .get(0);
+        assertEquals("utf8mb4_bin", column.getCollation());
+        assertEquals("VARCHAR", column.getDataType().getBaseTypeName());
+        column.setCollation("utf8mb4_general_ci");
+        TestUtils.assertStatementCanBeDeparsedAs(select,
+                sql("n VARCHAR(10) COLLATE utf8mb4_general_ci PATH '$.n'"), true);
+        parse(select.toString());
+        column.setCollation(null);
+        TestUtils.assertStatementCanBeDeparsedAs(select, sql("n VARCHAR(10) PATH '$.n'"), true);
+        parse(select.toString());
+        JsonTableValueColumnDefinition constructed = new JsonTableValueColumnDefinition()
+                .setColumnName("v")
+                .setDataType(new ColDataType("VARCHAR").addArgumentsStringList("10"))
+                .setCollation("utf8mb4_bin").setPathExpression(new StringValue("$.v"));
+        table.getColumnsClause().getColumnDefinitions().set(0, constructed);
+        TestUtils.assertStatementCanBeDeparsedAs(select,
+                sql("v VARCHAR(10) COLLATE utf8mb4_bin PATH '$.v'"), true);
+        parse(select.toString());
+    }
+
+    @Test
+    void columnCollationRequiresMySqlDialect() {
+        String sql = sql("n VARCHAR(10) COLLATE utf8mb4_bin PATH '$.n'");
+        assertThrows(JSQLParserException.class, () -> CCJSqlParserUtil.parse(sql));
+        assertThrows(JSQLParserException.class,
+                () -> CCJSqlParserUtil.parse(sql,
+                        parser -> parser.withDialect(Dialect.POSTGRESQL)));
+    }
+
+    private static PlainSelect parse(String sql) throws JSQLParserException {
+        return (PlainSelect) TestUtils.assertSqlCanBeParsedAndDeparsed(sql, true,
+                parser -> parser.withDialect(Dialect.MYSQL));
+    }
+
+    private static String sql(String column) {
+        return "SELECT * FROM JSON_TABLE('[{\"n\":\"ab\"}]', '$[*]' COLUMNS (" + column
+                + ")) AS jt";
+    }
+}