!99 feat: 添加 SQL CONCAT 函数支持

Merge pull request !99 from 王帅/main

mybatis-flex-core/src/main/java/com/mybatisflex/core/query/ArithmeticQueryColumn.java

@@ -96,7 +96,7 @@ public class ArithmeticQueryColumn extends QueryColumn {
             sql.append(arithmeticInfos.get(i).toSql(queryTables, dialect, i));
         }
         if (StringUtil.isNotBlank(alias)) {
-            return WrapperUtil.withAlias(sql.toString(), dialect.wrap(alias), dialect);
+            return WrapperUtil.withAlias(sql.toString(), alias, dialect);
         }
         return sql.toString();
     }

mybatis-flex-core/src/main/java/com/mybatisflex/core/query/CaseQueryColumn.java

@@ -44,7 +44,7 @@ public class CaseQueryColumn extends QueryColumn implements HasParamsColumn {
     String toSelectSql(List<QueryTable> queryTables, IDialect dialect) {
         String sql = buildSql(queryTables, dialect);
         if (StringUtil.isNotBlank(alias)) {
-            return WrapperUtil.withAlias(sql, dialect.wrap(alias), dialect);
+            return WrapperUtil.withAlias(sql, alias, dialect);
         }
         return sql;
     }

mybatis-flex-core/src/main/java/com/mybatisflex/core/query/CaseSearchQueryColumn.java

@@ -37,7 +37,7 @@ public class CaseSearchQueryColumn extends QueryColumn implements HasParamsColum
     String toSelectSql(List<QueryTable> queryTables, IDialect dialect) {
         String sql = buildSql(queryTables, dialect);
         if (StringUtil.isNotBlank(alias)) {
-            return WrapperUtil.withAlias(sql, dialect.wrap(alias), dialect);
+            return WrapperUtil.withAlias(sql, alias, dialect);
         }
         return sql;
     }

mybatis-flex-core/src/main/java/com/mybatisflex/core/query/FunctionQueryColumn.java

@@ -18,11 +18,15 @@ package com.mybatisflex.core.query;
 import com.mybatisflex.core.FlexConsts;
 import com.mybatisflex.core.constant.SqlConsts;
 import com.mybatisflex.core.dialect.IDialect;
-import com.mybatisflex.core.util.ObjectUtil;
+import com.mybatisflex.core.util.CollectionUtil;
 import com.mybatisflex.core.util.SqlUtil;
 import com.mybatisflex.core.util.StringUtil;
 
+import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
 
 /**
  * 数据库 聚合函数，例如 count(id) ，max(account.age) 等等
@@ -30,19 +34,25 @@ import java.util.List;
 public class FunctionQueryColumn extends QueryColumn implements HasParamsColumn {
 
     protected String fnName;
-    protected QueryColumn column;
+    protected List<QueryColumn> columns;
 
-    public FunctionQueryColumn(String fnName, String column) {
+    public FunctionQueryColumn(String fnName) {
         SqlUtil.keepColumnSafely(fnName);
-        SqlUtil.keepColumnSafely(column);
         this.fnName = fnName;
-        this.column = new QueryColumn(column);
+        this.columns = new ArrayList<>();
     }
 
-    public FunctionQueryColumn(String fnName, QueryColumn column) {
+    public FunctionQueryColumn(String fnName, String... columns) {
-        SqlUtil.keepColumnSafely(fnName);
+        this(fnName);
-        this.fnName = fnName;
+        for (String column : columns) {
-        this.column = column;
+            // SqlUtil.keepColumnSafely(column)
+            this.columns.add(new QueryColumn(column));
+        }
+    }
+
+    public FunctionQueryColumn(String fnName, QueryColumn... columns) {
+        this(fnName);
+        this.columns.addAll(Arrays.asList(columns));
     }
 
     public String getFnName() {
@@ -53,41 +63,73 @@ public class FunctionQueryColumn extends QueryColumn implements HasParamsColumn
         this.fnName = fnName;
     }
 
-    public QueryColumn getColumn() {
+    public List<QueryColumn> getColumns() {
-        return column;
+        return columns;
     }
 
-    public void setColumn(QueryColumn column) {
+    public void setColumns(List<QueryColumn> columns) {
-        this.column = column;
+        this.columns = columns;
     }
 
     @Override
     public Object[] getParamValues() {
-        if (column instanceof HasParamsColumn) {
+        if (CollectionUtil.isEmpty(columns)) {
-            return ((HasParamsColumn) column).getParamValues();
+            return FlexConsts.EMPTY_ARRAY;
         }
-        return FlexConsts.EMPTY_ARRAY;
+
+        List<Object> params = new ArrayList<>();
+
+        for (QueryColumn queryColumn : columns) {
+            if (queryColumn instanceof HasParamsColumn) {
+                Object[] paramValues = ((HasParamsColumn) queryColumn).getParamValues();
+                params.addAll(Arrays.asList(paramValues));
+            }
+        }
+
+        return params.toArray();
     }
 
     @Override
     public String toSelectSql(List<QueryTable> queryTables, IDialect dialect) {
-        String sql = column.toSelectSql(queryTables, dialect);
+        String sql = getSql(queryTables, dialect);
-        if (StringUtil.isBlank(sql)) {
-            return SqlConsts.EMPTY;
-        }
         if (StringUtil.isBlank(alias)) {
             return fnName + WrapperUtil.withBracket(sql);
         }
-        return fnName + WrapperUtil.withAlias(sql, dialect.wrap(alias), dialect);
+        return fnName + WrapperUtil.withAlias(sql, alias, dialect);
     }
 
     @Override
     String toConditionSql(List<QueryTable> queryTables, IDialect dialect) {
-        String sql = column.toSelectSql(queryTables, dialect);
+        String sql = getSql(queryTables, dialect);
+        return fnName + WrapperUtil.withBracket(sql);
+    }
+
+    /**
+     * <p>获取函数括号里面的 SQL 内容。
+     *
+     * <p>如果函数括号里面没有内容，就返回空字符串，这样构建出来就是函数名加括号。
+     *
+     * <p>例如，NOW() 函数的构建：
+     * <pre>{@code
+     * FunctionQueryColumn c1 = new FunctionQueryColumn("NOW");
+     * FunctionQueryColumn c2 = new FunctionQueryColumn("NOW", new StringQueryColumn(""));
+     * }</pre>
+     */
+    private String getSql(List<QueryTable> queryTables, IDialect dialect) {
+        if (CollectionUtil.isEmpty(columns)) {
+            return SqlConsts.EMPTY;
+        }
+
+        String sql = columns.stream()
+                .filter(Objects::nonNull)
+                .map(c -> c.toSelectSql(queryTables, dialect))
+                .collect(Collectors.joining(SqlConsts.DELIMITER));
+
         if (StringUtil.isBlank(sql)) {
             return SqlConsts.EMPTY;
         }
-        return fnName + WrapperUtil.withBracket(sql);
+
+        return sql;
     }
 
     @Override
@@ -101,7 +143,7 @@ public class FunctionQueryColumn extends QueryColumn implements HasParamsColumn
     public String toString() {
         return "FunctionQueryColumn{" +
                 "fnName='" + fnName + '\'' +
-                ", column=" + column +
+                ", columns=" + columns +
                 '}';
     }
 
@@ -109,7 +151,7 @@ public class FunctionQueryColumn extends QueryColumn implements HasParamsColumn
     public FunctionQueryColumn clone() {
         FunctionQueryColumn clone = (FunctionQueryColumn) super.clone();
         // deep clone ...
-        clone.column = ObjectUtil.clone(this.column);
+        clone.columns = CollectionUtil.cloneArrayList(this.columns);
         return clone;
     }
 

mybatis-flex-core/src/main/java/com/mybatisflex/core/query/QueryMethods.java

@@ -18,6 +18,9 @@ package com.mybatisflex.core.query;
 import com.mybatisflex.core.util.LambdaGetter;
 import com.mybatisflex.core.util.LambdaUtil;
 
+import java.util.Arrays;
+import java.util.List;
+
 import static com.mybatisflex.core.constant.SqlConsts.*;
 
 public class QueryMethods {
@@ -163,6 +166,15 @@ public class QueryMethods {
         return new StringFunctionQueryColumn(CONVERT, params);
     }
 
+    ///CONCAT
+    public static FunctionQueryColumn concat(String str1, String str2, String... more) {
+        List<String> args = Arrays.asList(str1, str2);
+        args.addAll(Arrays.asList(more));
+        String[] columns = new String[args.size()];
+        args.toArray(columns);
+        return new FunctionQueryColumn("CONCAT", columns);
+    }
+
     public static StringQueryColumn column(String column) {
         return new StringQueryColumn(column);
     }

mybatis-flex-core/src/main/java/com/mybatisflex/core/query/SelectQueryColumn.java

@@ -45,7 +45,7 @@ public class SelectQueryColumn extends QueryColumn implements HasParamsColumn {
     String toSelectSql(List<QueryTable> queryTables, IDialect dialect) {
         String selectSql = dialect.forSelectByQuery(queryWrapper);
         if (StringUtil.isNotBlank(selectSql) && StringUtil.isNotBlank(alias)) {
-            selectSql = WrapperUtil.withAlias(selectSql, dialect.wrap(alias), dialect);
+            selectSql = WrapperUtil.withAlias(selectSql, alias, dialect);
         }
         return selectSql;
     }

mybatis-flex-core/src/main/java/com/mybatisflex/core/query/SelectQueryTable.java

@@ -49,7 +49,7 @@ public class SelectQueryTable extends QueryTable {
     public String toSql(IDialect dialect) {
         String sql = dialect.buildSelectSql(queryWrapper);
         if (StringUtil.isNotBlank(alias)) {
-            return WrapperUtil.withAlias(sql, dialect.wrap(alias), dialect);
+            return WrapperUtil.withAlias(sql, alias, dialect);
         } else {
             return WrapperUtil.withBracket(sql);
         }

mybatis-flex-core/src/main/java/com/mybatisflex/core/query/StringFunctionQueryColumn.java

@@ -65,7 +65,7 @@ public class StringFunctionQueryColumn extends QueryColumn {
         if (StringUtil.isBlank(alias)) {
             return fnName + WrapperUtil.withBracket(sql);
         }
-        return fnName + WrapperUtil.withAlias(sql, dialect.wrap(alias), dialect);
+        return fnName + WrapperUtil.withAlias(sql, alias, dialect);
     }
 
     @Override

mybatis-flex-core/src/main/java/com/mybatisflex/core/query/WrapperUtil.java

@@ -147,7 +147,7 @@ class WrapperUtil {
     }
 
     static String withAlias(String sql, String alias, IDialect dialect) {
-        return SqlConsts.BRACKET_LEFT + sql + SqlConsts.BRACKET_RIGHT + getAsKeyWord(dialect) + alias;
+        return SqlConsts.BRACKET_LEFT + sql + SqlConsts.BRACKET_RIGHT + getAsKeyWord(dialect) + dialect.wrap(alias);
     }
 
     static String buildAlias(String alias, IDialect dialect) {

mybatis-flex-core/src/test/java/com/mybatisflex/coretest/FunctionSqlTest.java

@@ -0,0 +1,43 @@
+/*
+ *  Copyright (c) 2022-2023, Mybatis-Flex (fuhai999@gmail.com).
+ *  <p>
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *  <p>
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *  <p>
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package com.mybatisflex.coretest;
+
+import com.mybatisflex.core.query.FunctionQueryColumn;
+import com.mybatisflex.core.query.QueryWrapper;
+import com.mybatisflex.core.query.StringQueryColumn;
+import org.junit.Test;
+
+import static com.mybatisflex.coretest.table.AccountTableDef.ACCOUNT;
+
+/**
+ * @author 王帅
+ * @since 2023-06-28
+ */
+public class FunctionSqlTest {
+
+    @Test
+    public void test() {
+        String sql = QueryWrapper.create()
+                .select(new FunctionQueryColumn("NOW").as("n1"))
+                .select(new FunctionQueryColumn("NOW", new StringQueryColumn("")).as("n2"))
+                .select(new FunctionQueryColumn("CONCAT", ACCOUNT.USER_NAME, ACCOUNT.AGE).as("c1"))
+                .from(ACCOUNT)
+                .toSQL();
+        System.out.println(sql);
+    }
+
+}