Rui Wang created BEAM-5963:
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Summary: LPAD
Key: BEAM-5963
URL: https://issues.apache.org/jira/browse/BEAM-5963
Project: Beam
Issue Type: Sub-task
Components: dsl-sql
Reporter: Rui Wang
Assignee: Rui Wang
LPAD(original_value, return_length[, pattern])
Returns a value that consists of original_value prepended with pattern. The
return_length is an INT64 that specifies the length of the returned value. If
original_value is BYTES, return_length is the number of bytes. If
original_value is STRING, return_length is the number of characters.
The default value of pattern is a blank space.
Both original_value and pattern must be the same data type.
If return_length is less than or equal to the original_value length, this
function returns the original_value value, truncated to the value of
return_length. For example, LPAD("hello world", 7); returns "hello w".
If original_value, return_length, or pattern is NULL, this function returns
NULL.
This function returns an error if:
return_length is negative
pattern is empty
Return type
STRING or BYTES
Examples
SELECT t, len, FORMAT("%T", LPAD(t, len)) AS LPAD FROM UNNEST([
STRUCT('abc' AS t, 5 AS len),
('abc', 2),
('例子', 4)
]);
t len LPAD
abc 5 " abc"
abc 2 "ab"
例子 4 " 例子"
SELECT t, len, pattern, FORMAT("%T", LPAD(t, len, pattern)) AS LPAD FROM
UNNEST([
STRUCT('abc' AS t, 8 AS len, 'def' AS pattern),
('abc', 5, '-'),
('例子', 5, '中文')
]);
t len pattern LPAD
abc 8 def "defdeabc"
abc 5 - "--abc"
例子 5 中文 "中文中例子"
SELECT FORMAT("%T", t) AS t, len, FORMAT("%T", LPAD(t, len)) AS LPAD FROM
UNNEST([
STRUCT(b'abc' AS t, 5 AS len),
(b'abc', 2),
(b'\xab\xcd\xef', 4)
]);
t len LPAD
b"abc" 5 b" abc"
b"abc" 2 b"ab"
b"\xab\xcd\xef" 4 b" \xab\xcd\xef"
SELECT
FORMAT("%T", t) AS t,
len,
FORMAT("%T", pattern) AS pattern,
FORMAT("%T", LPAD(t, len, pattern)) AS LPAD
FROM UNNEST([
STRUCT(b'abc' AS t, 8 AS len, b'def' AS pattern),
(b'abc', 5, b'-'),
(b'\xab\xcd\xef', 5, b'\x00')
]);
t len pattern LPAD
b"abc" 8 b"def" b"defdeabc"
b"abc" 5 b"-" b"--abc"
b"\xab\xcd\xef" 5 b"\x00" b"\x00\x00\xab\xcd\xef"
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