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The following commit(s) were added to refs/heads/master by this push:
new ba7d2db [Function] Support utf-8 encoding in instr, locate,
locate_pos, lpad, rpad (#3638)
ba7d2db is described below
commit ba7d2dbf7b7c7dfe9fd4483a10dad07be5083b9b
Author: yangzhg <780531...@qq.com>
AuthorDate: Fri May 22 14:34:26 2020 +0800
[Function] Support utf-8 encoding in instr, locate, locate_pos, lpad, rpad
(#3638)
Support utf-8 encoding for string function `instr`, `locate`, `locate_pos`,
`lpad`, `rpad`
and add unit test for them
---
be/src/exprs/string_functions.cpp | 111 +++++++++++++++++----
be/test/exprs/string_functions_test.cpp | 89 ++++++++++++++++-
docs/.vuepress/sidebar/en.js | 1 +
docs/.vuepress/sidebar/zh-CN.js | 1 +
.../sql-functions/string-functions/lpad.md | 4 +-
.../string-functions/{lpad.md => rpad.md} | 20 ++--
.../sql-functions/string-functions/lpad.md | 2 +-
.../string-functions/{lpad.md => rpad.md} | 20 ++--
8 files changed, 201 insertions(+), 47 deletions(-)
diff --git a/be/src/exprs/string_functions.cpp
b/be/src/exprs/string_functions.cpp
index b02bf56..998794c 100644
--- a/be/src/exprs/string_functions.cpp
+++ b/be/src/exprs/string_functions.cpp
@@ -49,6 +49,15 @@ size_t get_utf8_byte_length(unsigned char byte) {
}
return char_size;
}
+size_t get_char_len(const StringVal& str, std::vector<size_t>* str_index) {
+ size_t char_len = 0;
+ for (size_t i = 0, char_size = 0; i < str.len; i += char_size) {
+ char_size = get_utf8_byte_length((unsigned)(str.ptr)[i]);
+ str_index->push_back(i);
+ ++char_len;
+ }
+ return char_len;
+}
// This behaves identically to the mysql implementation, namely:
// - 1-indexed positions
@@ -73,8 +82,7 @@ StringVal StringFunctions::substring(
std::vector<size_t> index;
for (size_t i = 0, char_size = 0; i < str.len; i += char_size) {
char_size = get_utf8_byte_length((unsigned)(str.ptr)[i]);
- index.push_back(byte_pos);
- byte_pos += char_size;
+ index.push_back(i);
if (pos.val > 0 && index.size() > pos.val + len.val) {
break;
}
@@ -196,28 +204,45 @@ StringVal StringFunctions::lpad(
if (str.is_null || len.is_null || pad.is_null || len.val < 0) {
return StringVal::null();
}
+
+ std::vector<size_t> str_index;
+ size_t str_char_size = get_char_len(str, &str_index);
+ std::vector<size_t> pad_index;
+ size_t pad_char_size = get_char_len(pad, &pad_index);
+
// Corner cases: Shrink the original string, or leave it alone.
// TODO: Hive seems to go into an infinite loop if pad.len == 0,
// so we should pay attention to Hive's future solution to be compatible.
- if (len.val <= str.len || pad.len == 0) {
- return StringVal(str.ptr, len.val);
+ if (len.val <= str_char_size || pad.len == 0) {
+ if (len.val > str_index.size()) {
+ return StringVal::null();
+ }
+ if (len.val == str_index.size()) {
+ return StringVal(str.ptr, len.val);
+ }
+ return StringVal(str.ptr, str_index[len.val]);
}
// TODO pengyubing
// StringVal result = StringVal::create_temp_string_val(context, len.val);
- StringVal result(context, len.val);
+ int32_t pad_byte_len = 0;
+ int32_t pad_times = (len.val - str_char_size) / pad_char_size;
+ int32_t pad_remainder = (len.val - str_char_size) % pad_char_size;
+ pad_byte_len = pad_times * pad.len;
+ pad_byte_len += pad_index[pad_remainder];
+ int32_t byte_len = str.len + pad_byte_len;
+ StringVal result(context, byte_len);
if (result.is_null) {
return result;
}
- int padded_prefix_len = len.val - str.len;
- int pad_index = 0;
+ int pad_idx = 0;
int result_index = 0;
uint8_t* ptr = result.ptr;
// Prepend chars of pad.
- while (result_index < padded_prefix_len) {
- ptr[result_index++] = pad.ptr[pad_index++];
- pad_index = pad_index % pad.len;
+ while (result_index < pad_byte_len) {
+ ptr[result_index++] = pad.ptr[pad_idx++];
+ pad_idx = pad_idx % pad.len;
}
// Append given string.
@@ -231,16 +256,34 @@ StringVal StringFunctions::rpad(
if (str.is_null || len.is_null || pad.is_null || len.val < 0) {
return StringVal::null();
}
+
+ std::vector<size_t> str_index;
+ size_t str_char_size = get_char_len(str, &str_index);
+ std::vector<size_t> pad_index;
+ size_t pad_char_size = get_char_len(pad, &pad_index);
+
// Corner cases: Shrink the original string, or leave it alone.
// TODO: Hive seems to go into an infinite loop if pad->len == 0,
// so we should pay attention to Hive's future solution to be compatible.
- if (len.val <= str.len || pad.len == 0) {
- return StringVal(str.ptr, len.val);
+ if (len.val <= str_char_size || pad.len == 0) {
+ if (len.val > str_index.size()) {
+ return StringVal::null();
+ }
+ if (len.val == str_index.size()) {
+ return StringVal(str.ptr, len.val);
+ }
+ return StringVal(str.ptr, str_index[len.val]);
}
// TODO pengyubing
// StringVal result = StringVal::create_temp_string_val(context, len.val);
- StringVal result(context, len.val);
+ int32_t pad_byte_len = 0;
+ int32_t pad_times = (len.val - str_char_size) / pad_char_size;
+ int32_t pad_remainder = (len.val - str_char_size) % pad_char_size;
+ pad_byte_len = pad_times * pad.len;
+ pad_byte_len += pad_index[pad_remainder];
+ int32_t byte_len = str.len + pad_byte_len;
+ StringVal result(context, byte_len);
if (UNLIKELY(result.is_null)) {
return result;
}
@@ -248,11 +291,11 @@ StringVal StringFunctions::rpad(
// Append chars of pad until desired length
uint8_t* ptr = result.ptr;
- int pad_index = 0;
+ int pad_idx = 0;
int result_len = str.len;
- while (result_len < len.val) {
- ptr[result_len++] = pad.ptr[pad_index++];
- pad_index = pad_index % pad.len;
+ while (result_len < byte_len) {
+ ptr[result_len++] = pad.ptr[pad_idx++];
+ pad_idx = pad_idx % pad.len;
}
return result;
}
@@ -295,7 +338,6 @@ IntVal StringFunctions::char_utf8_length(FunctionContext*
context, const StringV
return IntVal::null();
}
size_t char_len = 0;
- std::vector<size_t> index;
for (size_t i = 0, char_size = 0; i < str.len; i += char_size) {
char_size = get_utf8_byte_length((unsigned)(str.ptr)[i]);
++char_len;
@@ -412,11 +454,24 @@ IntVal StringFunctions::instr(
if (str.is_null || substr.is_null) {
return IntVal::null();
}
+ if (substr.len == 0) {
+ return IntVal(1);
+ }
StringValue str_sv = StringValue::from_string_val(str);
StringValue substr_sv = StringValue::from_string_val(substr);
StringSearch search(&substr_sv);
// Hive returns positions starting from 1.
- return IntVal(search.search(&str_sv) + 1);
+ int loc = search.search(&str_sv);
+ if (loc > 0) {
+ size_t char_len = 0;
+ for (size_t i = 0, char_size = 0; i < loc; i += char_size) {
+ char_size = get_utf8_byte_length((unsigned)(str.ptr)[i]);
+ ++char_len;
+ }
+ loc = char_len;
+ }
+
+ return IntVal(loc + 1);
}
IntVal StringFunctions::locate(
@@ -430,20 +485,34 @@ IntVal StringFunctions::locate_pos(
if (str.is_null || substr.is_null || start_pos.is_null) {
return IntVal::null();
}
+ if (substr.len == 0) {
+ if (str.len == 0 && start_pos.val > 1) {
+ return IntVal(0);
+ }
+ return IntVal(start_pos.val);
+ }
// Hive returns 0 for *start_pos <= 0,
// but throws an exception for *start_pos > str->len.
// Since returning 0 seems to be Hive's error condition, return 0.
- if (start_pos.val <= 0 || start_pos.val > str.len) {
+ std::vector<size_t> index;
+ size_t char_len = get_char_len(str, &index);
+ if (start_pos.val <= 0 || start_pos.val > str.len || start_pos.val >
char_len) {
return IntVal(0);
}
StringValue substr_sv = StringValue::from_string_val(substr);
StringSearch search(&substr_sv);
// Input start_pos.val starts from 1.
StringValue adjusted_str(
- reinterpret_cast<char*>(str.ptr) + start_pos.val - 1, str.len -
start_pos.val + 1);
+ reinterpret_cast<char*>(str.ptr) + index[start_pos.val - 1], str.len -
index[start_pos.val - 1]);
int32_t match_pos = search.search(&adjusted_str);
if (match_pos >= 0) {
// Hive returns the position in the original string starting from 1.
+ size_t char_len = 0;
+ for (size_t i = 0, char_size = 0; i < match_pos; i += char_size) {
+ char_size = get_utf8_byte_length((unsigned)(adjusted_str.ptr)[i]);
+ ++char_len;
+ }
+ match_pos = char_len;
return IntVal(start_pos.val + match_pos);
} else {
return IntVal(0);
diff --git a/be/test/exprs/string_functions_test.cpp
b/be/test/exprs/string_functions_test.cpp
index 2670f57..7320759 100644
--- a/be/test/exprs/string_functions_test.cpp
+++ b/be/test/exprs/string_functions_test.cpp
@@ -68,9 +68,6 @@ TEST_F(StringFunctionsTest, money_format_large_int) {
ss << str;
__int128 value;
ss >> value;
-
- std::cout << "value: " << value << std::endl;
-
StringVal result = StringFunctions::money_format(context,
doris_udf::LargeIntVal(value));
StringVal expected = AnyValUtil::from_string_temp(context,
std::string("170,141,183,460,469,231,731,687,303,715,884,105,727.00"));
ASSERT_EQ(expected, result);
@@ -361,6 +358,92 @@ TEST_F(StringFunctionsTest,
append_trailing_char_if_absent) {
StringVal("a"), StringVal("abc")));
}
+TEST_F(StringFunctionsTest, instr) {
+ doris_udf::FunctionContext* context = new doris_udf::FunctionContext();
+ ASSERT_EQ(IntVal(4), StringFunctions::instr(context,
StringVal("foobarbar"), StringVal("bar")));
+ ASSERT_EQ(IntVal(0), StringFunctions::instr(context, StringVal("foobar"),
StringVal("xbar")));
+ ASSERT_EQ(IntVal(2), StringFunctions::instr(context,
StringVal("123456234"), StringVal("234")));
+ ASSERT_EQ(IntVal(0), StringFunctions::instr(context, StringVal("123456"),
StringVal("567")));
+ ASSERT_EQ(IntVal(2), StringFunctions::instr(context, StringVal("1.234"),
StringVal(".234")));
+ ASSERT_EQ(IntVal(1), StringFunctions::instr(context, StringVal("1.234"),
StringVal("")));
+ ASSERT_EQ(IntVal(0), StringFunctions::instr(context, StringVal(""),
StringVal("123")));
+ ASSERT_EQ(IntVal(1), StringFunctions::instr(context, StringVal(""),
StringVal("")));
+ ASSERT_EQ(IntVal(3), StringFunctions::instr(context, StringVal("你好世界"),
StringVal("世界")));
+ ASSERT_EQ(IntVal(0), StringFunctions::instr(context, StringVal("你好世界"),
StringVal("您好")));
+ ASSERT_EQ(IntVal(3), StringFunctions::instr(context, StringVal("你好abc"),
StringVal("a")));
+ ASSERT_EQ(IntVal(3), StringFunctions::instr(context, StringVal("你好abc"),
StringVal("abc")));
+ ASSERT_EQ(IntVal::null(), StringFunctions::instr(context,
StringVal::null(), StringVal("2")));
+ ASSERT_EQ(IntVal::null(), StringFunctions::instr(context, StringVal(""),
StringVal::null()));
+ ASSERT_EQ(IntVal::null(), StringFunctions::instr(context,
StringVal::null(), StringVal::null()));
+}
+
+TEST_F(StringFunctionsTest, locate) {
+ doris_udf::FunctionContext* context = new doris_udf::FunctionContext();
+ ASSERT_EQ(IntVal(4), StringFunctions::locate(context, StringVal("bar"),
StringVal("foobarbar")));
+ ASSERT_EQ(IntVal(0), StringFunctions::locate(context, StringVal("xbar"),
StringVal("foobar")));
+ ASSERT_EQ(IntVal(2), StringFunctions::locate(context, StringVal("234"),
StringVal("123456234")));
+ ASSERT_EQ(IntVal(0), StringFunctions::locate(context, StringVal("567"),
StringVal("123456")));
+ ASSERT_EQ(IntVal(2), StringFunctions::locate(context, StringVal(".234"),
StringVal("1.234")));
+ ASSERT_EQ(IntVal(1), StringFunctions::locate(context, StringVal(""),
StringVal("1.234")));
+ ASSERT_EQ(IntVal(0), StringFunctions::locate(context, StringVal("123"),
StringVal("")));
+ ASSERT_EQ(IntVal(1), StringFunctions::locate(context, StringVal(""),
StringVal("")));
+ ASSERT_EQ(IntVal(3), StringFunctions::locate(context, StringVal("世界"),
StringVal("你好世界")));
+ ASSERT_EQ(IntVal(0), StringFunctions::locate(context, StringVal("您好"),
StringVal("你好世界")));
+ ASSERT_EQ(IntVal(3), StringFunctions::locate(context, StringVal("a"),
StringVal("你好abc")));
+ ASSERT_EQ(IntVal(3), StringFunctions::locate(context, StringVal("abc"),
StringVal("你好abc")));
+ ASSERT_EQ(IntVal::null(), StringFunctions::locate(context,
StringVal::null(), StringVal("2")));
+ ASSERT_EQ(IntVal::null(), StringFunctions::locate(context, StringVal(""),
StringVal::null()));
+ ASSERT_EQ(IntVal::null(), StringFunctions::locate(context,
StringVal::null(), StringVal::null()));
+}
+
+TEST_F(StringFunctionsTest, locate_pos) {
+ doris_udf::FunctionContext* context = new doris_udf::FunctionContext();
+ ASSERT_EQ(IntVal(7), StringFunctions::locate_pos(context,
StringVal("bar"), StringVal("foobarbar"), IntVal(5)));
+ ASSERT_EQ(IntVal(0), StringFunctions::locate_pos(context,
StringVal("xbar"), StringVal("foobar"), IntVal(1)));
+ ASSERT_EQ(IntVal(2), StringFunctions::locate_pos(context, StringVal(""),
StringVal("foobar"), IntVal(2)));
+ ASSERT_EQ(IntVal(0), StringFunctions::locate_pos(context,
StringVal("foobar"), StringVal(""), IntVal(1)));
+ ASSERT_EQ(IntVal(0), StringFunctions::locate_pos(context, StringVal(""),
StringVal(""), IntVal(2)));
+ ASSERT_EQ(IntVal(0), StringFunctions::locate_pos(context, StringVal("A"),
StringVal("AAAAAA"), IntVal(0)));
+ ASSERT_EQ(IntVal(0), StringFunctions::locate_pos(context, StringVal("A"),
StringVal("大A写的A"), IntVal(0)));
+ ASSERT_EQ(IntVal(2), StringFunctions::locate_pos(context, StringVal("A"),
StringVal("大A写的A"), IntVal(1)));
+ ASSERT_EQ(IntVal(2), StringFunctions::locate_pos(context, StringVal("A"),
StringVal("大A写的A"), IntVal(2)));
+ ASSERT_EQ(IntVal(5), StringFunctions::locate_pos(context, StringVal("A"),
StringVal("大A写的A"), IntVal(3)));
+ ASSERT_EQ(IntVal(7), StringFunctions::locate_pos(context,
StringVal("BaR"), StringVal("foobarBaR"), IntVal(5)));
+ ASSERT_EQ(IntVal::null(), StringFunctions::locate_pos(context,
StringVal::null(), StringVal("2"), IntVal(1)));
+ ASSERT_EQ(IntVal::null(), StringFunctions::locate_pos(context,
StringVal(""), StringVal::null(), IntVal(4)));
+ ASSERT_EQ(IntVal::null(), StringFunctions::locate_pos(context,
StringVal::null(), StringVal::null(), IntVal(4)));
+ ASSERT_EQ(IntVal::null(), StringFunctions::locate_pos(context,
StringVal::null(), StringVal::null(), IntVal(-1)));
+}
+
+TEST_F(StringFunctionsTest, lpad) {
+ ASSERT_EQ(StringVal("???hi"), StringFunctions::lpad(ctx, StringVal("hi"),
IntVal(5), StringVal("?")));
+ ASSERT_EQ(StringVal("g8%7IgY%AHx7luNtf8Kh"), StringFunctions::lpad(ctx,
StringVal("g8%7IgY%AHx7luNtf8Kh"), IntVal(20), StringVal("")));
+ ASSERT_EQ(StringVal("h"), StringFunctions::lpad(ctx, StringVal("hi"),
IntVal(1), StringVal("?")));
+ ASSERT_EQ(StringVal("你"), StringFunctions::lpad(ctx, StringVal("你好"),
IntVal(1), StringVal("?")));
+ ASSERT_EQ(StringVal(""), StringFunctions::lpad(ctx, StringVal("hi"),
IntVal(0), StringVal("?")));
+ ASSERT_EQ(StringVal::null(), StringFunctions::lpad(ctx, StringVal("hi"),
IntVal(-1), StringVal("?")));
+ ASSERT_EQ(StringVal("h"), StringFunctions::lpad(ctx, StringVal("hi"),
IntVal(1), StringVal("")));
+ ASSERT_EQ(StringVal::null(), StringFunctions::lpad(ctx, StringVal("hi"),
IntVal(5), StringVal("")));
+ ASSERT_EQ(StringVal("abahi"), StringFunctions::lpad(ctx, StringVal("hi"),
IntVal(5), StringVal("ab")));
+ ASSERT_EQ(StringVal("ababhi"), StringFunctions::lpad(ctx, StringVal("hi"),
IntVal(6), StringVal("ab")));
+ ASSERT_EQ(StringVal("呵呵呵hi"), StringFunctions::lpad(ctx, StringVal("hi"),
IntVal(5), StringVal("呵呵")));
+ ASSERT_EQ(StringVal("hih呵呵"), StringFunctions::lpad(ctx, StringVal("呵呵"),
IntVal(5), StringVal("hi")));
+}
+
+TEST_F(StringFunctionsTest, rpad) {
+ ASSERT_EQ(StringVal("hi???"), StringFunctions::rpad(ctx, StringVal("hi"),
IntVal(5), StringVal("?")));
+ ASSERT_EQ(StringVal("g8%7IgY%AHx7luNtf8Kh"), StringFunctions::rpad(ctx,
StringVal("g8%7IgY%AHx7luNtf8Kh"), IntVal(20), StringVal("")));
+ ASSERT_EQ(StringVal("h"), StringFunctions::rpad(ctx, StringVal("hi"),
IntVal(1), StringVal("?")));
+ ASSERT_EQ(StringVal("你"), StringFunctions::rpad(ctx, StringVal("你好"),
IntVal(1), StringVal("?")));
+ ASSERT_EQ(StringVal(""), StringFunctions::rpad(ctx, StringVal("hi"),
IntVal(0), StringVal("?")));
+ ASSERT_EQ(StringVal::null(), StringFunctions::rpad(ctx, StringVal("hi"),
IntVal(-1), StringVal("?")));
+ ASSERT_EQ(StringVal("h"), StringFunctions::rpad(ctx, StringVal("hi"),
IntVal(1), StringVal("")));
+ ASSERT_EQ(StringVal::null(), StringFunctions::rpad(ctx, StringVal("hi"),
IntVal(5), StringVal("")));
+ ASSERT_EQ(StringVal("hiaba"), StringFunctions::rpad(ctx, StringVal("hi"),
IntVal(5), StringVal("ab")));
+ ASSERT_EQ(StringVal("hiabab"), StringFunctions::rpad(ctx, StringVal("hi"),
IntVal(6), StringVal("ab")));
+ ASSERT_EQ(StringVal("hi呵呵呵"), StringFunctions::rpad(ctx, StringVal("hi"),
IntVal(5), StringVal("呵呵")));
+ ASSERT_EQ(StringVal("呵呵hih"), StringFunctions::rpad(ctx, StringVal("呵呵"),
IntVal(5), StringVal("hi")));
+}
}
int main(int argc, char** argv) {
diff --git a/docs/.vuepress/sidebar/en.js b/docs/.vuepress/sidebar/en.js
index f293bb8..5efadc5 100644
--- a/docs/.vuepress/sidebar/en.js
+++ b/docs/.vuepress/sidebar/en.js
@@ -221,6 +221,7 @@ module.exports = [
"regexp_replace",
"repeat",
"right",
+ "rpad",
"split_part",
"starts_with",
"strleft",
diff --git a/docs/.vuepress/sidebar/zh-CN.js b/docs/.vuepress/sidebar/zh-CN.js
index 9c4fde2..e2d3bd5 100644
--- a/docs/.vuepress/sidebar/zh-CN.js
+++ b/docs/.vuepress/sidebar/zh-CN.js
@@ -233,6 +233,7 @@ module.exports = [
"regexp_replace",
"repeat",
"right",
+ "rpad",
"split_part",
"starts_with",
"strleft",
diff --git a/docs/en/sql-reference/sql-functions/string-functions/lpad.md
b/docs/en/sql-reference/sql-functions/string-functions/lpad.md
index 1751cff..686748a 100644
--- a/docs/en/sql-reference/sql-functions/string-functions/lpad.md
+++ b/docs/en/sql-reference/sql-functions/string-functions/lpad.md
@@ -28,10 +28,10 @@ under the License.
## Description
### Syntax
-'VARCHAR lpad (VARCHAR str., INT len, VARCHAR pad)'
+'VARCHAR lpad (VARCHAR str, INT len, VARCHAR pad)'
-Returns a string of length len in str, starting with the initials. If len is
longer than str, pad characters are added to STR until the length of the string
reaches len. If len is less than str's length, the function is equivalent to
truncating STR strings and returning only strings of len's length.
+Returns a string of length len in str, starting with the initials. If len is
longer than str, pad characters are added to STR until the length of the string
reaches len. If len is less than str's length, the function is equivalent to
truncating STR strings and returning only strings of len's length. The len is
character length not the bye size.
## example
diff --git a/docs/en/sql-reference/sql-functions/string-functions/lpad.md
b/docs/en/sql-reference/sql-functions/string-functions/rpad.md
similarity index 67%
copy from docs/en/sql-reference/sql-functions/string-functions/lpad.md
copy to docs/en/sql-reference/sql-functions/string-functions/rpad.md
index 1751cff..232916f 100644
--- a/docs/en/sql-reference/sql-functions/string-functions/lpad.md
+++ b/docs/en/sql-reference/sql-functions/string-functions/rpad.md
@@ -1,6 +1,6 @@
---
{
- "title": "lpad",
+ "title": "rpad",
"language": "en"
}
---
@@ -24,31 +24,31 @@ specific language governing permissions and limitations
under the License.
-->
-# lpad
+# rpad
## Description
### Syntax
-'VARCHAR lpad (VARCHAR str., INT len, VARCHAR pad)'
+'VARCHAR rpad (VARCHAR str, INT len, VARCHAR pad)'
-Returns a string of length len in str, starting with the initials. If len is
longer than str, pad characters are added to STR until the length of the string
reaches len. If len is less than str's length, the function is equivalent to
truncating STR strings and returning only strings of len's length.
+Returns a string of length len in str, starting with the initials. If len is
longer than str, pad characters are added to the right of STR until the length
of the string reaches len. If len is less than str's length, the function is
equivalent to truncating STR strings and returning only strings of len's
length. The len is character length not the bye size.
## example
```
-mysql> SELECT lpad("hi", 5, "xy");
+mysql> SELECT rpad("hi", 5, "xy");
+---------------------+
-| lpad('hi', 5, 'xy') |
+| rpad('hi', 5, 'xy') |
+---------------------+
-| xyxhi |
+| hixyx |
+---------------------+
-mysql> SELECT lpad("hi", 1, "xy");
+mysql> SELECT rpad("hi", 1, "xy");
+---------------------+
-| lpad('hi', 1, 'xy') |
+| rpad('hi', 1, 'xy') |
+---------------------+
| h |
+---------------------+
```
##keyword
-LPAD
+RPAD
diff --git a/docs/zh-CN/sql-reference/sql-functions/string-functions/lpad.md
b/docs/zh-CN/sql-reference/sql-functions/string-functions/lpad.md
index 62ea2cd..1173c2c 100644
--- a/docs/zh-CN/sql-reference/sql-functions/string-functions/lpad.md
+++ b/docs/zh-CN/sql-reference/sql-functions/string-functions/lpad.md
@@ -31,7 +31,7 @@ under the License.
`VARCHAR lpad(VARCHAR str, INT len, VARCHAR pad)`
-返回 str 中长度为 len（从首字母开始算起）的字符串。如果 len 大于 str 的长度，则在 str 的前面不断补充 pad
字符，直到该字符串的长度达到 len 为止。如果 len 小于 str 的长度，该函数相当于截断 str 字符串，只返回长度为 len 的字符串。
+返回 str 中长度为 len（从首字母开始算起）的字符串。如果 len 大于 str 的长度，则在 str 的前面不断补充 pad
字符，直到该字符串的长度达到 len 为止。如果 len 小于 str 的长度，该函数相当于截断 str 字符串，只返回长度为 len 的字符串。len
指的是字符长度而不是字节长度。
## example
diff --git a/docs/zh-CN/sql-reference/sql-functions/string-functions/lpad.md
b/docs/zh-CN/sql-reference/sql-functions/string-functions/rpad.md
similarity index 75%
copy from docs/zh-CN/sql-reference/sql-functions/string-functions/lpad.md
copy to docs/zh-CN/sql-reference/sql-functions/string-functions/rpad.md
index 62ea2cd..28c3fdb 100644
--- a/docs/zh-CN/sql-reference/sql-functions/string-functions/lpad.md
+++ b/docs/zh-CN/sql-reference/sql-functions/string-functions/rpad.md
@@ -1,6 +1,6 @@
---
{
- "title": "lpad",
+ "title": "rpad",
"language": "zh-CN"
}
---
@@ -24,31 +24,31 @@ specific language governing permissions and limitations
under the License.
-->
-# lpad
+# rpad
## description
### Syntax
-`VARCHAR lpad(VARCHAR str, INT len, VARCHAR pad)`
+`VARCHAR rpad(VARCHAR str, INT len, VARCHAR pad)`
-返回 str 中长度为 len（从首字母开始算起）的字符串。如果 len 大于 str 的长度，则在 str 的前面不断补充 pad
字符，直到该字符串的长度达到 len 为止。如果 len 小于 str 的长度，该函数相当于截断 str 字符串，只返回长度为 len 的字符串。
+返回 str 中长度为 len（从首字母开始算起）的字符串。如果 len 大于 str 的长度，则在 str 的后面不断补充 pad
字符，直到该字符串的长度达到 len 为止。如果 len 小于 str 的长度，该函数相当于截断 str 字符串，只返回长度为 len 的字符串。len
指的是字符长度而不是字节长度。
## example
```
-mysql> SELECT lpad("hi", 5, "xy");
+mysql> SELECT rpad("hi", 5, "xy");
+---------------------+
-| lpad('hi', 5, 'xy') |
+| rpad('hi', 5, 'xy') |
+---------------------+
-| xyxhi |
+| hixyx |
+---------------------+
-mysql> SELECT lpad("hi", 1, "xy");
+mysql> SELECT rpad("hi", 1, "xy");
+---------------------+
-| lpad('hi', 1, 'xy') |
+| rpad('hi', 1, 'xy') |
+---------------------+
| h |
+---------------------+
```
##keyword
-LPAD
+RPAD
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