/
func_concat.result
172 lines (162 loc) · 3.28 KB
/
func_concat.result
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SET sql_mode=ORACLE;
EXPLAIN EXTENDED SELECT 'a'||'b'||'c';
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select 'a' || 'b' || 'c' AS "'a'||'b'||'c'"
SELECT '' || '';
'' || ''
SELECT '' || 'b';
'' || 'b'
b
SELECT '' || NULL;
'' || NULL
SELECT 'a' || '';
'a' || ''
a
SELECT 'a' || 'b';
'a' || 'b'
ab
SELECT 'a' || NULL;
'a' || NULL
a
SELECT NULL || '';
NULL || ''
SELECT NULL || 'b';
NULL || 'b'
b
SELECT NULL || NULL;
NULL || NULL
NULL
SELECT '' || '' || '';
'' || '' || ''
SELECT '' || '' || 'c';
'' || '' || 'c'
c
SELECT '' || '' || NULL;
'' || '' || NULL
SELECT '' || 'b' || '';
'' || 'b' || ''
b
SELECT '' || 'b' || 'c';
'' || 'b' || 'c'
bc
SELECT '' || 'b' || NULL;
'' || 'b' || NULL
b
SELECT '' || NULL || '';
'' || NULL || ''
SELECT '' || NULL || 'c';
'' || NULL || 'c'
c
SELECT '' || NULL || NULL;
'' || NULL || NULL
SELECT 'a' || '' || '';
'a' || '' || ''
a
SELECT 'a' || '' || 'c';
'a' || '' || 'c'
ac
SELECT 'a' || '' || NULL;
'a' || '' || NULL
a
SELECT 'a' || 'b' || '';
'a' || 'b' || ''
ab
SELECT 'a' || 'b' || 'c';
'a' || 'b' || 'c'
abc
SELECT 'a' || 'b' || NULL;
'a' || 'b' || NULL
ab
SELECT 'a' || NULL || '';
'a' || NULL || ''
a
SELECT 'a' || NULL || 'c';
'a' || NULL || 'c'
ac
SELECT 'a' || NULL || NULL;
'a' || NULL || NULL
a
SELECT NULL || '' || '';
NULL || '' || ''
SELECT NULL || '' || 'c';
NULL || '' || 'c'
c
SELECT NULL || '' || NULL;
NULL || '' || NULL
SELECT NULL || 'b' || '';
NULL || 'b' || ''
b
SELECT NULL || 'b' || 'c';
NULL || 'b' || 'c'
bc
SELECT NULL || 'b' || NULL;
NULL || 'b' || NULL
b
SELECT NULL || NULL || '';
NULL || NULL || ''
SELECT NULL || NULL || 'c';
NULL || NULL || 'c'
c
SELECT NULL || NULL || NULL;
NULL || NULL || NULL
NULL
CREATE TABLE t1 (a VARCHAR(10), b VARCHAR(10), c VARCHAR(10));
INSERT INTO t1 VALUES ('', '', '');
INSERT INTO t1 VALUES ('', '', 'c');
INSERT INTO t1 VALUES ('', '', NULL);
INSERT INTO t1 VALUES ('', 'b', '');
INSERT INTO t1 VALUES ('', 'b', 'c');
INSERT INTO t1 VALUES ('', 'b', NULL);
INSERT INTO t1 VALUES ('', NULL, '');
INSERT INTO t1 VALUES ('', NULL, 'c');
INSERT INTO t1 VALUES ('', NULL, NULL);
INSERT INTO t1 VALUES ('a', '', '');
INSERT INTO t1 VALUES ('a', '', 'c');
INSERT INTO t1 VALUES ('a', '', NULL);
INSERT INTO t1 VALUES ('a', 'b', '');
INSERT INTO t1 VALUES ('a', 'b', 'c');
INSERT INTO t1 VALUES ('a', 'b', NULL);
INSERT INTO t1 VALUES ('a', NULL, '');
INSERT INTO t1 VALUES ('a', NULL, 'c');
INSERT INTO t1 VALUES ('a', NULL, NULL);
INSERT INTO t1 VALUES (NULL, '', '');
INSERT INTO t1 VALUES (NULL, '', 'c');
INSERT INTO t1 VALUES (NULL, '', NULL);
INSERT INTO t1 VALUES (NULL, 'b', '');
INSERT INTO t1 VALUES (NULL, 'b', 'c');
INSERT INTO t1 VALUES (NULL, 'b', NULL);
INSERT INTO t1 VALUES (NULL, NULL, '');
INSERT INTO t1 VALUES (NULL, NULL, 'c');
INSERT INTO t1 VALUES (NULL, NULL, NULL);
SELECT LENGTH(a||b||c), a||b||c FROM t1 ORDER BY a,b,c;
LENGTH(a||b||c) a||b||c
NULL NULL
0
1 c
0
0
1 c
1 b
1 b
2 bc
0
0
1 c
0
0
1 c
1 b
1 b
2 bc
1 a
1 a
2 ac
1 a
1 a
2 ac
2 ab
2 ab
3 abc
DROP TABLE t1;