[GitHub] [incubator-doris] morningman commented on a change in pull request #4347: udf: str_replace function

[GitBox <gi...@apache.org>]

morningman commented on a change in pull request #4347:
URL: https://github.com/apache/incubator-doris/pull/4347#discussion_r470004948



##########
File path: docs/zh-CN/sql-reference/sql-functions/string-functions/str_replace.md
##########
@@ -0,0 +1,46 @@
+---
+{
+    "title": "str_replace",

Review comment:
       In MySQL, this function named `replace()`, so better to name it as `replace()`

##########
File path: docs/en/sql-reference/sql-functions/string-functions/str_replace.md
##########
@@ -0,0 +1,46 @@
+---
+{
+    "title": "str_replace",
+    "language": "zh-CN"
+}
+---
+
+<!--
+Licensed to the Apache Software Foundation (ASF) under one
+or more contributor license agreements.  See the NOTICE file
+distributed with this work for additional information
+regarding copyright ownership.  The ASF licenses this file
+to you 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
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+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.
+-->
+
+# str_replace
+## description
+### Syntax
+
+`VARCHAR STR_REPLACE (VARCHAR str, VARCHAR old, VARCHAR new)`
+
+replace all old substring with new substring in str 
+
+## example
+
+```
+mysql> select str_replace("http://www.baidu.com:9090", "9090", "");
++------------------------------------------------------+
+| str_replace('http://www.baidu.com:9090', '9090', '') |
++------------------------------------------------------+
+| http://www.baidu.com:                                |
++------------------------------------------------------+
+```
+##keyword

Review comment:
       ```suggestion
   ## keyword
   ```

##########
File path: be/src/exprs/string_functions.cpp
##########
@@ -998,4 +998,23 @@ StringVal StringFunctions::split_part(FunctionContext* context, const StringVal&
     int len = (find[field.val - 1] == -1 ? content.len : find[field.val - 1]) - start_pos;
     return StringVal(content.ptr + start_pos, len);
 }
+
+StringVal StringFunctions::str_replace(FunctionContext *context, const StringVal &origStr, const StringVal &oldStr, const StringVal &newStr) {
+    if (origStr.is_null || oldStr.is_null || newStr.is_null) {
+        return origStr;

Review comment:
       Should return null if any of them is null

##########
File path: be/test/exprs/string_functions_test.cpp
##########
@@ -494,6 +494,19 @@ TEST_F(StringFunctionsTest, rpad) {
     ASSERT_EQ(StringVal("呵呵hih"),
               StringFunctions::rpad(ctx, StringVal("呵呵"), IntVal(5), StringVal("hi")));
 }
+
+TEST_F(StringFunctionsTest, str_replace) {
+    ASSERT_EQ(StringVal("http://www.baidu.com:8080"),
+            StringFunctions::str_replace(ctx, StringVal("http://www.baidu.com:9090"), StringVal("9090"), StringVal("8080")));
+
+    ASSERT_EQ(StringVal("http://www.baidu.com:9090"),
+        StringFunctions::str_replace(ctx, StringVal("http://www.baidu.com:9090"), StringVal("9070"), StringVal("8080")));
+    ASSERT_EQ(StringVal("http://www.baidu.com:9090"),
+        StringFunctions::str_replace(ctx, StringVal("http://www.baidu.com:9090"), StringVal(""), StringVal("8080")));
+    ASSERT_EQ(StringVal("http://www.baidu.com:"),
+        StringFunctions::str_replace(ctx, StringVal("http://www.baidu.com:9090"), StringVal("9090"), StringVal("")));

Review comment:
       Better to add more tests to test to corner case, like `null`, `empty string`, `expr2 longer than expr1`, Chinese char, etc...




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