strings.sql

来自「postgresql8.3.4源码,开源数据库」· SQL 代码 · 共 453 行 · 第 1/2 页

--
-- STRINGS
-- Test various data entry syntaxes.
--

-- SQL92 string continuation syntax
-- E021-03 character string literals
SELECT 'first line'
' - next line'
	' - third line'
	AS "Three lines to one";

-- illegal string continuation syntax
SELECT 'first line'
' - next line' /* this comment is not allowed here */
' - third line'
	AS "Illegal comment within continuation";

--
-- test conversions between various string types
-- E021-10 implicit casting among the character data types
--

SELECT CAST(f1 AS text) AS "text(char)" FROM CHAR_TBL;

SELECT CAST(f1 AS text) AS "text(varchar)" FROM VARCHAR_TBL;

SELECT CAST(name 'namefield' AS text) AS "text(name)";

-- since this is an explicit cast, it should truncate w/o error:
SELECT CAST(f1 AS char(10)) AS "char(text)" FROM TEXT_TBL;
-- note: implicit-cast case is tested in char.sql

SELECT CAST(f1 AS char(20)) AS "char(text)" FROM TEXT_TBL;

SELECT CAST(f1 AS char(10)) AS "char(varchar)" FROM VARCHAR_TBL;

SELECT CAST(name 'namefield' AS char(10)) AS "char(name)";

SELECT CAST(f1 AS varchar) AS "varchar(text)" FROM TEXT_TBL;

SELECT CAST(f1 AS varchar) AS "varchar(char)" FROM CHAR_TBL;

SELECT CAST(name 'namefield' AS varchar) AS "varchar(name)";

--
-- test SQL92 string functions
-- E### and T### are feature reference numbers from SQL99
--

-- E021-09 trim function
SELECT TRIM(BOTH FROM '  bunch o blanks  ') = 'bunch o blanks' AS "bunch o blanks";

SELECT TRIM(LEADING FROM '  bunch o blanks  ') = 'bunch o blanks  ' AS "bunch o blanks  ";

SELECT TRIM(TRAILING FROM '  bunch o blanks  ') = '  bunch o blanks' AS "  bunch o blanks";

SELECT TRIM(BOTH 'x' FROM 'xxxxxsome Xsxxxxx') = 'some Xs' AS "some Xs";

-- E021-06 substring expression
SELECT SUBSTRING('1234567890' FROM 3) = '34567890' AS "34567890";

SELECT SUBSTRING('1234567890' FROM 4 FOR 3) = '456' AS "456";

-- T581 regular expression substring (with SQL99's bizarre regexp syntax)
SELECT SUBSTRING('abcdefg' FROM 'a#"(b_d)#"%' FOR '#') AS "bcd";

-- No match should return NULL
SELECT SUBSTRING('abcdefg' FROM '#"(b_d)#"%' FOR '#') IS NULL AS "True";

-- Null inputs should return NULL
SELECT SUBSTRING('abcdefg' FROM '(b|c)' FOR NULL) IS NULL AS "True";
SELECT SUBSTRING(NULL FROM '(b|c)' FOR '#') IS NULL AS "True";
SELECT SUBSTRING('abcdefg' FROM NULL FOR '#') IS NULL AS "True";

-- PostgreSQL extension to allow omitting the escape character;
-- here the regexp is taken as Posix syntax
SELECT SUBSTRING('abcdefg' FROM 'c.e') AS "cde";

-- With a parenthesized subexpression, return only what matches the subexpr
SELECT SUBSTRING('abcdefg' FROM 'b(.*)f') AS "cde";

-- PostgreSQL extension to allow using back reference in replace string;
SELECT regexp_replace('1112223333', E'(\\d{3})(\\d{3})(\\d{4})', E'(\\1) \\2-\\3');
SELECT regexp_replace('AAA   BBB   CCC   ', E'\\s+', ' ', 'g');
SELECT regexp_replace('AAA', '^|$', 'Z', 'g');
SELECT regexp_replace('AAA aaa', 'A+', 'Z', 'gi');
-- invalid regexp option
SELECT regexp_replace('AAA aaa', 'A+', 'Z', 'z');

-- set so we can tell NULL from empty string
\pset null '\\N'

-- return all matches from regexp
SELECT regexp_matches('foobarbequebaz', $re$(bar)(beque)$re$);

-- test case insensitive
SELECT regexp_matches('foObARbEqUEbAz', $re$(bar)(beque)$re$, 'i');

-- global option - more than one match
SELECT regexp_matches('foobarbequebazilbarfbonk', $re$(b[^b]+)(b[^b]+)$re$, 'g');

-- empty capture group (matched empty string)
SELECT regexp_matches('foobarbequebaz', $re$(bar)(.*)(beque)$re$);
-- no match
SELECT regexp_matches('foobarbequebaz', $re$(bar)(.+)(beque)$re$);
-- optional capture group did not match, null entry in array
SELECT regexp_matches('foobarbequebaz', $re$(bar)(.+)?(beque)$re$);

-- no capture groups
SELECT regexp_matches('foobarbequebaz', $re$barbeque$re$);

-- give me errors
SELECT regexp_matches('foobarbequebaz', $re$(bar)(beque)$re$, 'gz');
SELECT regexp_matches('foobarbequebaz', $re$(barbeque$re$);
SELECT regexp_matches('foobarbequebaz', $re$(bar)(beque){2,1}$re$);

-- split string on regexp
SELECT foo, length(foo) FROM regexp_split_to_table('the quick brown fox jumped over the lazy dog', $re$\s+$re$) AS foo;
SELECT regexp_split_to_array('the quick brown fox jumped over the lazy dog', $re$\s+$re$);

SELECT foo, length(foo) FROM regexp_split_to_table('the quick brown fox jumped over the lazy dog', $re$\s*$re$) AS foo;
SELECT regexp_split_to_array('the quick brown fox jumped over the lazy dog', $re$\s*$re$);
SELECT foo, length(foo) FROM regexp_split_to_table('the quick brown fox jumped over the lazy dog', '') AS foo;
SELECT regexp_split_to_array('the quick brown fox jumped over the lazy dog', '');
-- case insensitive
SELECT foo, length(foo) FROM regexp_split_to_table('thE QUick bROWn FOx jUMPed ovEr THE lazy dOG', 'e', 'i') AS foo;
SELECT regexp_split_to_array('thE QUick bROWn FOx jUMPed ovEr THE lazy dOG', 'e', 'i');
-- no match of pattern
SELECT foo, length(foo) FROM regexp_split_to_table('the quick brown fox jumped over the lazy dog', 'nomatch') AS foo;
SELECT regexp_split_to_array('the quick brown fox jumped over the lazy dog', 'nomatch');
-- some corner cases
SELECT regexp_split_to_array('123456','1');
SELECT regexp_split_to_array('123456','6');
SELECT regexp_split_to_array('123456','.');
-- errors
SELECT foo, length(foo) FROM regexp_split_to_table('thE QUick bROWn FOx jUMPed ovEr THE lazy dOG', 'e', 'zippy') AS foo;
SELECT regexp_split_to_array('thE QUick bROWn FOx jUMPed ovEr THE lazy dOG', 'e', 'iz');
-- global option meaningless for regexp_split
SELECT foo, length(foo) FROM regexp_split_to_table('thE QUick bROWn FOx jUMPed ovEr THE lazy dOG', 'e', 'g') AS foo;
SELECT regexp_split_to_array('thE QUick bROWn FOx jUMPed ovEr THE lazy dOG', 'e', 'g');

-- change NULL-display back
\pset null ''

-- E021-11 position expression
SELECT POSITION('4' IN '1234567890') = '4' AS "4";

SELECT POSITION('5' IN '1234567890') = '5' AS "5";

-- T312 character overlay function
SELECT OVERLAY('abcdef' PLACING '45' FROM 4) AS "abc45f";

SELECT OVERLAY('yabadoo' PLACING 'daba' FROM 5) AS "yabadaba";

SELECT OVERLAY('yabadoo' PLACING 'daba' FROM 5 FOR 0) AS "yabadabadoo";

SELECT OVERLAY('babosa' PLACING 'ubb' FROM 2 FOR 4) AS "bubba";

--
-- test LIKE
-- Be sure to form every test as a LIKE/NOT LIKE pair.
--

-- simplest examples
-- E061-04 like predicate
SELECT 'hawkeye' LIKE 'h%' AS "true";
SELECT 'hawkeye' NOT LIKE 'h%' AS "false";

SELECT 'hawkeye' LIKE 'H%' AS "false";
SELECT 'hawkeye' NOT LIKE 'H%' AS "true";

SELECT 'hawkeye' LIKE 'indio%' AS "false";
SELECT 'hawkeye' NOT LIKE 'indio%' AS "true";

SELECT 'hawkeye' LIKE 'h%eye' AS "true";
SELECT 'hawkeye' NOT LIKE 'h%eye' AS "false";

SELECT 'indio' LIKE '_ndio' AS "true";
SELECT 'indio' NOT LIKE '_ndio' AS "false";

SELECT 'indio' LIKE 'in__o' AS "true";
SELECT 'indio' NOT LIKE 'in__o' AS "false";

SELECT 'indio' LIKE 'in_o' AS "false";
SELECT 'indio' NOT LIKE 'in_o' AS "true";

-- unused escape character
SELECT 'hawkeye' LIKE 'h%' ESCAPE '#' AS "true";
SELECT 'hawkeye' NOT LIKE 'h%' ESCAPE '#' AS "false";

SELECT 'indio' LIKE 'ind_o' ESCAPE '$' AS "true";
SELECT 'indio' NOT LIKE 'ind_o' ESCAPE '$' AS "false";

-- escape character
-- E061-05 like predicate with escape clause
SELECT 'h%' LIKE 'h#%' ESCAPE '#' AS "true";
SELECT 'h%' NOT LIKE 'h#%' ESCAPE '#' AS "false";

SELECT 'h%wkeye' LIKE 'h#%' ESCAPE '#' AS "false";
SELECT 'h%wkeye' NOT LIKE 'h#%' ESCAPE '#' AS "true";

SELECT 'h%wkeye' LIKE 'h#%%' ESCAPE '#' AS "true";
SELECT 'h%wkeye' NOT LIKE 'h#%%' ESCAPE '#' AS "false";

SELECT 'h%awkeye' LIKE 'h#%a%k%e' ESCAPE '#' AS "true";
SELECT 'h%awkeye' NOT LIKE 'h#%a%k%e' ESCAPE '#' AS "false";

SELECT 'indio' LIKE '_ndio' ESCAPE '$' AS "true";
SELECT 'indio' NOT LIKE '_ndio' ESCAPE '$' AS "false";

SELECT 'i_dio' LIKE 'i$_d_o' ESCAPE '$' AS "true";
SELECT 'i_dio' NOT LIKE 'i$_d_o' ESCAPE '$' AS "false";

SELECT 'i_dio' LIKE 'i$_nd_o' ESCAPE '$' AS "false";
SELECT 'i_dio' NOT LIKE 'i$_nd_o' ESCAPE '$' AS "true";

SELECT 'i_dio' LIKE 'i$_d%o' ESCAPE '$' AS "true";
SELECT 'i_dio' NOT LIKE 'i$_d%o' ESCAPE '$' AS "false";

-- escape character same as pattern character
SELECT 'maca' LIKE 'm%aca' ESCAPE '%' AS "true";
SELECT 'maca' NOT LIKE 'm%aca' ESCAPE '%' AS "false";

SELECT 'ma%a' LIKE 'm%a%%a' ESCAPE '%' AS "true";
SELECT 'ma%a' NOT LIKE 'm%a%%a' ESCAPE '%' AS "false";