1.1、初始测试数据
表结构：TEST_TB_GRADE
Sql代码:
create table TEST_TB_GRADE
(
ID NUMBER(10) not null,
USER_NAME VARCHAR2(20 CHAR),
COURSE VARCHAR2(20 CHAR),
SCORE FLOAT
)
1.2、 如果需要实现如下的查询效果图：
这就是最常见的行转列，主要原理是利用decode函数、聚集函数(sum)，结合group by分组实现的，具体的sql如下：
Sql代码:
select t.user_name,
sum(decode(t.course, '语文', score,null)) as CHINESE,
sum(decode(t.course, '数学', score,null)) as MATH,
sum(decode(t.course, '英语', score,null)) as ENGLISH
from test_tb_grade t
group by t.user_name
order by t.user_name
1.3、延伸
如果要实现对各门功课的不同分数段进行统计，效果图如下：
具体的实现sql如下：
Sql代码:
select t2.SCORE_GP,
sum(decode(t2.course, '语文', COUNTNUM,null)) as CHINESE,
sum(decode(t2.course, '数学', COUNTNUM,null)) as MATH,
sum(decode(t2.course, '英语', COUNTNUM,null)) as ENGLISH
from (
select t.course,
case when t.score <60 then '00-60'
when t.score >=60 and t.score <80 then '60-80'
when t.score >=80 then '80-100' end as SCORE_GP,
count(t.score) as COUNTNUM
FROM test_tb_grade t
group by t.course,
case when t.score <60 then '00-60'
when t.score >=60 and t.score <80 then '60-80'
when t.score >=80 then '80-100' end
order by t.course ) t2
group by t2.SCORE_GP
order by t2.SCORE_GP
二、列转行
1.1、初始测试数据
表结构： TEST_TB_GRADE2
Sql代码:
create table TEST_TB_GRADE2
(
ID NUMBER(10) not null,
USER_NAME VARCHAR2(20 CHAR),
CN_SCORE FLOAT,
MATH_SCORE FLOAT,
EN_SCORE FLOAT
)
初始数据如下图：
1.2、 如果需要实现如下的查询效果图：
这就是最常见的列转行，主要原理是利用SQL里面的union，具体的sql语句如下：
Sql代码:
select user_name, 'CN_SCORE' COURSE , CN_SCORE as SCORE from test_tb_grade2
union
select user_name, 'MATH_SCORE' COURSE, MATH_SCORE as SCORE from test_tb_grade2 union
select user_name, 'EN_SCORE' COURSE, EN_SCORE as SCORE from test_tb_grade2
order by user_name,COURSE
也可以利用【insert all into ... select】来实现，首先需要先建一个表TEST_TB_GRADE3：
Sql代码:
create table TEST_TB_GRADE3
(
USER_NAME VARCHAR2(20 CHAR),
COURSE VARCHAR2(20 CHAR),
SCORE FLOAT
)
再执行下面的sql：
Sql代码:
insert all
into test_tb_grade3(USER_NAME,COURSE,SCORE) values(user_name, '语文', CN_SCORE)
into test_tb_grade3(USER_NAME,COURSE,SCORE) values(user_name, '数学', MATH_SCORE)
into test_tb_grade3(USER_NAME,COURSE,SCORE) values(user_name, '英语', EN_SCORE)
select user_name, CN_SCORE, MATH_SCORE, EN_SCORE from test_tb_grade2;
commit;
行列转换包括以下六种情况：
*列转行
*行转列
*多列转换成字符串
*多行转换成字符串
*字符串转换成多列
*字符串转换成多行
下面分别进行举例介绍。
首先声明一点，有些例子需要如下10g及以后才有的知识：
a。掌握model子句，
b。正则表达式
c。加强的层次查询
讨论的适用范围只包括8i,9i,10g及以后版本。begin：
1、列转行
CREATE TABLE t_col_row(
ID INT,
c1 VARCHAR2(10),
c2 VARCHAR2(10),
c3 VARCHAR2(10));
INSERT INTO t_col_row VALUES (1, 'v11', 'v21', 'v31');
INSERT INTO t_col_row VALUES (2, 'v12', 'v22', NULL);
INSERT INTO t_col_row VALUES (3, 'v13', NULL, 'v33');
INSERT INTO t_col_row VALUES (4, NULL, 'v24', 'v34');
INSERT INTO t_col_row VALUES (5, 'v15', NULL, NULL);
INSERT INTO t_col_row VALUES (6, NULL, NULL, 'v35');
INSERT INTO t_col_row VALUES (7, NULL, NULL, NULL);
COMMIT;
SELECT * FROM t_col_row;
1)UNION ALL
适用范围：8i,9i,10g及以后版本，但此方法是针对于固定行的
SELECT id, 'c1' cn, c1 cv
FROM t_col_row
UNION ALL
SELECT id, 'c2' cn, c2 cv
FROM t_col_row
UNION ALL
SELECT id, 'c3' cn, c3 cv FROM t_col_row;
若空行不需要转换，只需加一个where条件，
WHERE COLUMN IS NOT NULL 即可。
2)MODEL
适用范围：10g及以后
SELECT id, cn, cv FROM t_col_row
MODEL
RETURN UPDATED ROWS
PARTITION BY (ID)
DIMENSION BY (0 AS n)
MEASURES ('xx' AS cn,'yyy' AS cv,c1,c2,c3)
RULES UPSERT ALL
(
cn[1] = 'c1',
cn[2] = 'c2',
cn[3] = 'c3',
cv[1] = c1[0],
cv[2] = c2[0],
cv[3] = c3[0]
)
ORDER BY ID,cn;
3)collection
适用范围：8i,9i,10g及以后版本
要创建一个对象和一个集合：
CREATE TYPE cv_pair AS OBJECT(cn VARCHAR2(10),cv VARCHAR2(10));
CREATE TYPE cv_varr AS VARRAY(8) OF cv_pair;
SELECT id, t.cn AS cn, t.cv AS cv
FROM t_col_row,
TABLE(cv_varr(cv_pair('c1', t_col_row.c1),
cv_pair('c2', t_col_row.c2),
cv_pair('c3', t_col_row.c3))) t
ORDER BY 1, 2;
2、行转列
CREATE TABLE t_row_col AS
SELECT id, 'c1' cn, c1 cv
FROM t_col_row
UNION ALL
SELECT id, 'c2' cn, c2 cv
FROM t_col_row
UNION ALL
SELECT id, 'c3' cn, c3 cv FROM t_col_row;
SELECT * FROM t_row_col ORDER BY 1,2;
1)AGGREGATE FUNCTION
适用范围：8i,9i,10g及以后版本
SELECT id,
MAX(decode(cn, 'c1', cv, NULL)) AS c1,
MAX(decode(cn, 'c2', cv, NULL)) AS c2,
MAX(decode(cn, 'c3', cv, NULL)) AS c3
FROM t_row_col
GROUP BY id
ORDER BY 1;
MAX聚集函数也可以用sum、min、avg等其他聚集函数替代。
被指定的转置列只能有一列，但固定的列可以有多列，请看下面的例子：
SELECT mgr, deptno, empno, ename FROM emp ORDER BY 1, 2;
SELECT mgr,
deptno,
MAX(decode(empno, '7788', ename, NULL)) "7788",
MAX(decode(empno, '7902', ename, NULL)) "7902",
MAX(decode(empno, '7844', ename, NULL)) "7844",
MAX(decode(empno, '7521', ename, NULL)) "7521",
MAX(decode(empno, '7900', ename, NULL)) "7900",
MAX(decode(empno, '7499', ename, NULL)) "7499",
MAX(decode(empno, '7654', ename, NULL)) "7654"
FROM emp
WHERE mgr IN (7566, 7698)
AND deptno IN (20, 30)
GROUP BY mgr, deptno
ORDER BY 1, 2;
这里转置列为empno，固定列为mgr，deptno。
还有一种行转列的方式，就是相同组中的行值变为单个列值，但转置的行值不变为列名：
ID CN_1 CV_1 CN_2 CV_2 CN_3 CV_3
1 c1 v11 c2 v21 c3 v31
2 c1 v12 c2 v22 c3
3 c1 v13 c2 c3 v33
4 c1 c2 v24 c3 v34
5 c1 v15 c2 c3
6 c1 c2 c3 v35
7 c1 c2 c3
这种情况可以用分析函数实现：
SELECT id,
MAX(decode(rn, 1, cn, NULL)) cn_1,
MAX(decode(rn, 1, cv, NULL)) cv_1,
MAX(decode(rn, 2, cn, NULL)) cn_2,
MAX(decode(rn, 2, cv, NULL)) cv_2,
MAX(decode(rn, 3, cn, NULL)) cn_3,
MAX(decode(rn, 3, cv, NULL)) cv_3
FROM (SELECT id,
cn,
cv,
row_number() over(PARTITION BY id ORDER BY cn, cv) rn
FROM t_row_col)
GROUP BY ID;
2)PL/SQL
适用范围：8i,9i,10g及以后版本
这种对于行值不固定的情况可以使用。
下面是我写的一个包，包中
p_rows_column_real用于前述的第一种不限定列的转换；
p_rows_column用于前述的第二种不限定列的转换。
CREATE OR REPLACE PACKAGE pkg_dynamic_rows_column AS
TYPE refc IS REF CURSOR;
PROCEDURE p_print_sql(p_txt VARCHAR2);
FUNCTION f_split_str(p_str VARCHAR2, p_division VARCHAR2, p_seq INT)
RETURN VARCHAR2;
PROCEDURE p_rows_column(p_table IN VARCHAR2,
p_keep_cols IN VARCHAR2,
p_pivot_cols IN VARCHAR2,
p_where IN VARCHAR2 DEFAULT NULL,
p_refc IN OUT refc);
PROCEDURE p_rows_column_real(p_table IN VARCHAR2,
p_keep_cols IN VARCHAR2,
p_pivot_col IN VARCHAR2,
p_pivot_val IN VARCHAR2,
p_where IN VARCHAR2 DEFAULT NULL,
p_refc IN OUT refc);
END;
/
CREATE OR REPLACE PACKAGE BODY pkg_dynamic_rows_column AS
PROCEDURE p_print_sql(p_txt VARCHAR2) IS
v_len INT;
BEGIN
v_len := length(p_txt);
FOR i IN 1 .. v_len / 250 + 1 LOOP
dbms_output.put_line(substrb(p_txt, (i - 1) * 250 + 1, 250));
END LOOP;
END;
FUNCTION f_split_str(p_str VARCHAR2, p_division VARCHAR2, p_seq INT)
RETURN VARCHAR2 IS
v_first INT;
v_last INT;
BEGIN
IF p_seq < 1 THEN
RETURN NULL;
END IF;
IF p_seq = 1 THEN
IF instr(p_str, p_division, 1, p_seq) = 0 THEN
RETURN p_str;
ELSE
RETURN substr(p_str, 1, instr(p_str, p_division, 1) - 1);
END IF;
ELSE
v_first := instr(p_str, p_division, 1, p_seq - 1);
v_last := instr(p_str, p_division, 1, p_seq);
IF (v_last = 0) THEN
IF (v_first > 0) THEN
RETURN substr(p_str, v_first + 1);
ELSE
RETURN NULL;
END IF;
ELSE
RETURN substr(p_str, v_first + 1, v_last - v_first - 1);
END IF;
END IF;
END f_split_str;
PROCEDURE p_rows_column(p_table IN VARCHAR2,
p_keep_cols IN VARCHAR2,
p_pivot_cols IN VARCHAR2,
p_where IN VARCHAR2 DEFAULT NULL,
p_refc IN OUT refc) IS
v_sql VARCHAR2(4000);
TYPE v_keep_ind_by IS TABLE OF VARCHAR2(4000) INDEX BY BINARY_INTEGER;
v_keep v_keep_ind_by;
TYPE v_pivot_ind_by IS TABLE OF VARCHAR2(4000) INDEX BY BINARY_INTEGER;
v_pivot v_pivot_ind_by;
v_keep_cnt INT;
v_pivot_cnt INT;
v_max_cols INT;
v_partition VARCHAR2(4000);
v_partition1 VARCHAR2(4000);
v_partition2 VARCHAR2(4000);
BEGIN
v_keep_cnt := length(p_keep_cols) - length(REPLACE(p_keep_cols, ',')) + 1;
v_pivot_cnt := length(p_pivot_cols) -
length(REPLACE(p_pivot_cols, ',')) + 1;
FOR i IN 1 .. v_keep_cnt LOOP
v_keep(i) := f_split_str(p_keep_cols, ',', i);
END LOOP;
FOR j IN 1 .. v_pivot_cnt LOOP
v_pivot(j) := f_split_str(p_pivot_cols, ',', j);
END LOOP;
v_sql := 'select max(count(*)) from ' || p_table || ' group by ';
FOR i IN 1 .. v_keep.LAST LOOP
v_sql := v_sql || v_keep(i) || ',';
END LOOP;
v_sql := rtrim(v_sql, ',');
EXECUTE IMMEDIATE v_sql
INTO v_max_cols;
v_partition := 'select ';
FOR x IN 1 .. v_keep.COUNT LOOP
v_partition1 := v_partition1 || v_keep(x) || ',';
END LOOP;
FOR y IN 1 .. v_pivot.COUNT LOOP
v_partition2 := v_partition2 || v_pivot(y) || ',';
END LOOP;
v_partition1 := rtrim(v_partition1, ',');
v_partition2 := rtrim(v_partition2, ',');
v_partition := v_partition || v_partition1 || ',' || v_partition2 ||
', row_number() over (partition by ' || v_partition1 ||
' order by ' || v_partition2 || ') rn from ' || p_table;
v_partition := rtrim(v_partition, ',');
v_sql := 'select ';
FOR i IN 1 .. v_keep.COUNT LOOP
v_sql := v_sql || v_keep(i) || ',';
END LOOP;
FOR i IN 1 .. v_max_cols LOOP
FOR j IN 1 .. v_pivot.COUNT LOOP
v_sql := v_sql || ' max(decode(rn,' || i || ',' || v_pivot(j) ||
',null))' || v_pivot(j) || '_' || i || ',';
END LOOP;
END LOOP;
IF p_where IS NOT NULL THEN
v_sql := rtrim(v_sql, ',') || ' from (' || v_partition || ' ' ||
p_where || ') group by ';
ELSE
v_sql := rtrim(v_sql, ',') || ' from (' || v_partition ||
') group by ';
END IF;
FOR i IN 1 .. v_keep.COUNT LOOP
v_sql := v_sql || v_keep(i) || ',';
END LOOP;
v_sql := rtrim(v_sql, ',');
p_print_sql(v_sql);
OPEN p_refc FOR v_sql;
EXCEPTION
WHEN OTHERS THEN
OPEN p_refc FOR
SELECT 'x' FROM dual WHERE 0 = 1;
END;
PROCEDURE p_rows_column_real(p_table IN VARCHAR2,
p_keep_cols IN VARCHAR2,
p_pivot_col IN VARCHAR2,
p_pivot_val IN VARCHAR2,
p_where IN VARCHAR2 DEFAULT NULL,
p_refc IN OUT refc) IS
v_sql VARCHAR2(4000);
TYPE v_keep_ind_by IS TABLE OF VARCHAR2(4000) INDEX BY BINARY_INTEGER;
v_keep v_keep_ind_by;
TYPE v_pivot_ind_by IS TABLE OF VARCHAR2(4000) INDEX BY BINARY_INTEGER;
v_pivot v_pivot_ind_by;
v_keep_cnt INT;
v_group_by VARCHAR2(2000);
BEGIN
v_keep_cnt := length(p_keep_cols) - length(REPLACE(p_keep_cols, ',')) + 1;
FOR i IN 1 .. v_keep_cnt LOOP
v_keep(i) := f_split_str(p_keep_cols, ',', i);
END LOOP;
v_sql := 'select ' || 'cast(' || p_pivot_col ||
' as varchar2(200)) as ' || p_pivot_col || ' from ' || p_table ||
' group by ' || p_pivot_col;
EXECUTE IMMEDIATE v_sql BULK COLLECT
INTO v_pivot;
FOR i IN 1 .. v_keep.COUNT LOOP
v_group_by := v_group_by || v_keep(i) || ',';
END LOOP;
v_group_by := rtrim(v_group_by, ',');
v_sql := 'select ' || v_group_by || ',';
FOR x IN 1 .. v_pivot.COUNT LOOP
v_sql := v_sql || ' max(decode(' || p_pivot_col || ',' || chr(39) ||
v_pivot(x) || chr(39) || ',' || p_pivot_val ||
',null)) as "' || v_pivot(x) || '",';
END LOOP;
v_sql := rtrim(v_sql, ',');
IF p_where IS NOT NULL THEN
v_sql := v_sql || ' from ' || p_table || p_where || ' group by ' ||
v_group_by;
ELSE
v_sql := v_sql || ' from ' || p_table || ' group by ' || v_group_by;
END IF;
p_print_sql(v_sql);
OPEN p_refc FOR v_sql;
EXCEPTION
WHEN OTHERS THEN
OPEN p_refc FOR
SELECT 'x' FROM dual WHERE 0 = 1;
END;
END;
/
3.多列转换成字符串
CREATE TABLE t_col_str AS
SELECT * FROM t_col_row;
这个比较简单，用||或concat函数可以实现：
SELECT concat('a','b') FROM dual;
1)|| OR concat
适用范围：8i,9i,10g及以后版本
SELECT * FROM t_col_str;
SELECT ID,c1||','||c2||','||c3 AS c123
FROM t_col_str;
4.多行转换成字符串
CREATE TABLE t_row_str(
ID INT,
col VARCHAR2(10));
INSERT INTO t_row_str VALUES(1,'a');
INSERT INTO t_row_str VALUES(1,'b');
INSERT INTO t_row_str VALUES(1,'c');
INSERT INTO t_row_str VALUES(2,'a');
INSERT INTO t_row_str VALUES(2,'d');
INSERT INTO t_row_str VALUES(2,'e');
INSERT INTO t_row_str VALUES(3,'c');
COMMIT;
SELECT * FROM t_row_str;
1)MAX + decode
适用范围：8i,9i,10g及以后版本，但此方法固定了条数，下面的中每个种类最多有三行组成一个字串
SELECT id,
MAX(decode(rn, 1, col, NULL)) ||
MAX(decode(rn, 2, ',' || col, NULL)) ||
MAX(decode(rn, 3, ',' || col, NULL)) str
FROM (SELECT id,
col,
row_number() over(PARTITION BY id ORDER BY col) AS rn
FROM t_row_str) t
GROUP BY id
ORDER BY 1;
2)row_number + lead
适用范围：8i,9i,10g及以后版本，，但此方法固定了条数，下面的中每个种类最多有四行组成一个字串
SELECT id, str
FROM (SELECT id,
row_number() over(PARTITION BY id ORDER BY col) AS rn,
col || lead(',' || col, 1) over(PARTITION BY id ORDER BY col) ||
lead(',' || col, 2) over(PARTITION BY id ORDER BY col) ||
lead(',' || col, 3) over(PARTITION BY id ORDER BY col) AS str
FROM t_row_str)
WHERE rn = 1
ORDER BY 1;
3)MODEL
适用范围：10g及以后版本
SELECT id, substr(str, 2) str FROM t_row_str
MODEL
RETURN UPDATED ROWS
PARTITION BY(ID)
DIMENSION BY(row_number() over(PARTITION BY ID ORDER BY col) AS rn)
MEASURES (CAST(col AS VARCHAR2(20)) AS str)
RULES UPSERT
ITERATE(3) UNTIL( presentv(str[iteration_number+2],1,0)=0)
(str[0] = str[0] || ',' || str[iteration_number+1])
ORDER BY 1;
4)sys_connect_by_path
适用范围：8i,9i,10g及以后版本，此方法对组成字串的行数没有限制，可首选此方法
SELECT t.id id, MAX(substr(sys_connect_by_path(t.col, ','), 2)) str
FROM (SELECT id, col, row_number() over(PARTITION BY id ORDER BY col) rn
FROM t_row_str) t
START WITH rn = 1
CONNECT BY rn = PRIOR rn + 1
AND id = PRIOR id
GROUP BY t.id;
适用范围：10g及以后版本
SELECT t.id id, substr(sys_connect_by_path(t.col, ','), 2) str
FROM (SELECT id, col, row_number() over(PARTITION BY id ORDER BY col) rn
FROM t_row_str) t
WHERE connect_by_isleaf = 1
START WITH rn = 1
CONNECT BY rn = PRIOR rn + 1
AND id = PRIOR id;
5)wmsys.wm_concat
适用范围：10g及以后版本
这个函数预定义按','分隔字符串，若要用其他符号分隔可以用，replace将','替换。
SELECT id, REPLACE(wmsys.wm_concat(col), ',', '/')
FROM t_row_str
GROUP BY id;
5.字符串转换成多列
其实际上就是一个字符串拆分的问题。
CREATE TABLE t_str_col AS
SELECT ID,c1||','||c2||','||c3 AS c123
FROM t_col_str;
SELECT * FROM t_str_col;
1)substr + instr
适用范围：8i,9i,10g及以后版本
SELECT id,
c123,
substr(c123, 1, instr(c123 || ',', ',', 1, 1) - 1) c1,
substr(c123,
instr(c123 || ',', ',', 1, 1) + 1,
instr(c123 || ',', ',', 1, 2) - instr(c123 || ',', ',', 1, 1) - 1) c2,
substr(c123,
instr(c123 || ',', ',', 1, 2) + 1,
instr(c123 || ',', ',', 1, 3) - instr(c123 || ',', ',', 1, 2) - 1) c3
FROM t_str_col
ORDER BY 1;
2)regexp_substr
适用范围：10g及以后版本
SELECT id,
c123,
rtrim(regexp_substr(c123 || ',', '.*?' || ',', 1, 1), ',') AS c1,
rtrim(regexp_substr(c123 || ',', '.*?' || ',', 1, 2), ',') AS c2,
rtrim(regexp_substr(c123 || ',', '.*?' || ',', 1, 3), ',') AS c3
FROM t_str_col
ORDER BY 1;
6.字符串转换成多行
CREATE TABLE t_str_row AS
SELECT id,
MAX(decode(rn, 1, col, NULL)) ||
MAX(decode(rn, 2, ',' || col, NULL)) ||
MAX(decode(rn, 3, ',' || col, NULL)) str
FROM (SELECT id,
col,
row_number() over(PARTITION BY id ORDER BY col) AS rn
FROM t_row_str) t
GROUP BY id
ORDER BY 1;
SELECT * FROM t_str_row;
1)UNION ALL
适用范围：8i,9i,10g及以后版本
SELECT id, 1 AS p, substr(str, 1, instr(str || ',', ',', 1, 1) - 1) AS cv
FROM t_str_row
UNION ALL
SELECT id,
2 AS p,
substr(str,
instr(str || ',', ',', 1, 1) + 1,
instr(str || ',', ',', 1, 2) - instr(str || ',', ',', 1, 1) - 1) AS cv
FROM t_str_row
UNION ALL
SELECT id,
3 AS p,
substr(str,
instr(str || ',', ',', 1, 1) + 1,
instr(str || ',', ',', 1, 2) - instr(str || ',', ',', 1, 1) - 1) AS cv
FROM t_str_row
ORDER BY 1, 2;
适用范围：10g及以后版本
SELECT id, 1 AS p, rtrim(regexp_substr(str||',', '.*?' || ',', 1, 1), ',') AS cv
FROM t_str_row
UNION ALL
SELECT id, 2 AS p, rtrim(regexp_substr(str||',', '.*?' || ',', 1, 2), ',') AS cv
FROM t_str_row
UNION ALL
SELECT id, 3 AS p, rtrim(regexp_substr(str||',', '.*?' || ',',1,3), ',') AS cv
FROM t_str_row
ORDER BY 1, 2;
2)VARRAY
适用范围：8i,9i,10g及以后版本
要创建一个可变数组：
CREATE OR REPLACE TYPE ins_seq_type IS VARRAY(8) OF NUMBER;
SELECT * FROM TABLE(ins_seq_type(1, 2, 3, 4, 5));
SELECT t.id,
c.column_value AS p,
substr(t.ca,
instr(t.ca, ',', 1, c.column_value) + 1,
instr(t.ca, ',', 1, c.column_value + 1) -
(instr(t.ca, ',', 1, c.column_value) + 1)) AS cv
FROM (SELECT id,
',' || str || ',' AS ca,
length(str || ',') - nvl(length(REPLACE(str, ',')), 0) AS cnt
FROM t_str_row) t
INNER JOIN TABLE(ins_seq_type(1, 2, 3)) c ON c.column_value <=
t.cnt
ORDER BY 1, 2;
3)SEQUENCE series
这类方法主要是要产生一个连续的整数列，产生连续整数列的方法有很多，主要有：
CONNECT BY,ROWNUM+all_objects,CUBE等。
适用范围：8i,9i,10g及以后版本
SELECT t.id,
c.lv AS p,
substr(t.ca,
instr(t.ca, ',', 1, c.lv) + 1,
instr(t.ca, ',', 1, c.lv + 1) -
(instr(t.ca, ',', 1, c.lv) + 1)) AS cv
FROM (SELECT id,
',' || str || ',' AS ca,
length(str || ',') - nvl(length(REPLACE(str, ',')), 0) AS cnt
FROM t_str_row) t,
(SELECT LEVEL lv FROM dual CONNECT BY LEVEL <= 5) c
WHERE c.lv <= t.cnt
ORDER BY 1, 2;
SELECT t.id,
c.rn AS p,
substr(t.ca,
instr(t.ca, ',', 1, c.rn) + 1,
instr(t.ca, ',', 1, c.rn + 1) -
(instr(t.ca, ',', 1, c.rn) + 1)) AS cv
FROM (SELECT id,
',' || str || ',' AS ca,
length(str || ',') - nvl(length(REPLACE(str, ',')), 0) AS cnt
FROM t_str_row) t,
(SELECT rownum rn FROM all_objects WHERE rownum <= 5) c
WHERE c.rn <= t.cnt
ORDER BY 1, 2;
SELECT t.id,
c.cb AS p,
substr(t.ca,
instr(t.ca, ',', 1, c.cb) + 1,
instr(t.ca, ',', 1, c.cb + 1) -
(instr(t.ca, ',', 1, c.cb) + 1)) AS cv
FROM (SELECT id,
',' || str || ',' AS ca,
length(str || ',') - nvl(length(REPLACE(str, ',')), 0) AS cnt
FROM t_str_row) t,
(SELECT rownum cb FROM (SELECT 1 FROM dual GROUP BY CUBE(1, 2))) c
WHERE c.cb <= t.cnt
ORDER BY 1, 2;
适用范围：10g及以后版本
SELECT t.id,
c.lv AS p,
rtrim(regexp_substr(t.str || ',', '.*?' || ',', 1, c.lv), ',') AS cv
FROM (SELECT id,
str,
length(regexp_replace(str || ',', '[^' || ',' || ']', NULL)) AS cnt
FROM t_str_row) t
INNER JOIN (SELECT LEVEL lv FROM dual CONNECT BY LEVEL <= 5) c ON c.lv <=
t.cnt
ORDER BY 1, 2;
4)Hierarchical + DBMS_RANDOM
适用范围：10g及以后版本
SELECT id,
LEVEL AS p,
rtrim(regexp_substr(str || ',', '.*?' || ',', 1, LEVEL), ',') AS cv
FROM t_str_row
CONNECT BY id = PRIOR id
AND PRIOR dbms_random.VALUE IS NOT NULL
AND LEVEL <=
length(regexp_replace(str || ',', '[^' || ',' || ']', NULL))
ORDER BY 1, 2;
5)Hierarchical + CONNECT_BY_ROOT
适用范围：10g及以后版本
SELECT id,
LEVEL AS p,
rtrim(regexp_substr(str || ',', '.*?' || ',', 1, LEVEL), ',') AS cv
FROM t_str_row
CONNECT BY id = connect_by_root id
AND LEVEL <=
length(regexp_replace(str || ',', '[^' || ',' || ']', NULL))
ORDER BY 1, 2;
6)MODEL
适用范围：10g及以后版本
SELECT id, p, cv FROM t_str_row
MODEL
RETURN UPDATED ROWS
PARTITION BY(ID)
DIMENSION BY( 0 AS p)
MEASURES( str||',' AS cv)
RULES UPSERT
(cv
[ FOR p
FROM 1 TO length(regexp_replace(cv[0],'[^'||','||']',null))
INCREMENT 1
] = rtrim(regexp_substr( cv[0],'.*?'||',',1,cv(p)),','))
ORDER BY 1,2;
end.
listagg
在oracle 11g release 2 版本中新增的listagg函数，listagg是一个实现字符串聚合的oracle内建函数;
listagg(column,'分隔符') within group (order by column) over(partition by column)
分隔符可以为空，
order by必选项，可以order by null
(1)select status, listagg(risk_id, ',') within group (order by risk_id) from rp_risk group by status;
以status分组，将risk_id全部合并显示在一行
(2)与许多的聚合函数类似，listagg通过加上over()子句可以实现分析功能
select risk_id, status, listagg(risk_id, ',') within group (order by risk_id) over(partition by status) from rp_risk;
选出与当前risk_id在同一个部门的所有risk_id并合并字符串
(3)listagg聚合的结果列大小限制在varchar2类型的最大值内（比如4000);
(4)合并字符串也可以用wm_concat(column_name),所有版本的oracle都可以用这个函数
listagg()是oracle 11g release 2才有；
(5)参考链接
http://xpchild.blog.163.com/blog/static/10180985920108485721969/
Sql代码
--listagg(合并多行的值为字符串，只用一列来显示)
select status, count(*), listagg(risk_id, ',') within group (order by risk_id) from rp_risk group by status;
select risk_id, status, listagg(risk_id, ',') within group (order by risk_id) over(partition by status) from rp_risk;
select risk.risk_id, listagg(officer.last_name || ',' || officer.first_name, '; ') within group(order by null) from rp_risk risk, rp_risk_area_ref re, rp_risk_area area, rp_risk_officer officer
where risk.risk_id = re.risk_id
and re.risk_area_id = area.risk_area_id(+)
and area.risk_officer_id = officer.risk_officer_id(+)
group by risk.risk_id;
--pivot(行专列，将多行的值改为多列显示)(for in的那个column,是某个列的值，也就是将某个列的值作为新的列的column,这个column下边的值好像只能来自一列)
select * from
(select risk.risk_id, re.risk_area_order, officer.last_name || ',' || officer.first_name fullname
from rp_risk risk, rp_risk_area_ref re, rp_risk_area area, rp_risk_officer officer
where risk.risk_id = re.risk_id
and re.risk_area_id = area.risk_area_id(+)
and area.risk_officer_id = officer.risk_officer_id(+) order by risk.risk_id desc, re.risk_area_order)
pivot(max(fullname) for risk_area_order in (1 primaryOfficer, 2 addtionalOffcier1, 3 addtionalOffcier2)) order by risk_id desc;
--decode(行专列，将多行的值改为多列显示)(decode的那个column,是某个列的值，也就是将某个列的值作为新的列的column,MAX聚集函数也可以用sum、min、avg等其他聚集函数替代)
select risk_id,
--max(decode(risk_area_order, 1, fullname)) primaryOfficer,
--max(decode(risk_area_order, 2, fullname)) addtionalOffcier1,
--max(decode(risk_area_order, 3, fullname)) addtionalOffcier1
min(decode(risk_area_order, 1, fullname)) primaryOfficer,
min(decode(risk_area_order, 2, fullname)) addtionalOffcier1,
min(decode(risk_area_order, 3, fullname)) addtionalOffcier1
from
(select risk.risk_id, re.risk_area_order, officer.last_name || ',' || officer.first_name fullname from rp_risk risk, rp_risk_area_ref re, rp_risk_area area, rp_risk_officer officer
where risk.risk_id = re.risk_id
and re.risk_area_id = area.risk_area_id(+)
and area.risk_officer_id = officer.risk_officer_id(+) order by risk.risk_id, re.risk_area_order)
group by risk_id order by risk_id;
1.创建测试数据
CREATE TABLE CC
(Student NVARCHAR2(2),Course NVARCHAR2(2),Score INT
);
INSERT into CC
select N'张三',N'语文',78 from dual union all
select N'张三',N'数学',87 from dual union all
select N'张三',N'英语',82 from dual union all
select N'张三',N'物理',90 from dual union all
select N'李四',N'语文',65 from dual union all
select N'李四',N'数学',77 from dual union all
select N'李四',N'英语',65 from dual union all
select N'李四',N'物理',85 from dual ;
commit;
希望看到查询結果:
李四 77 85 65 65 292
张三 87 90 82 78 337
2.使用wm_concat方法
SELECT STUDENT,WM_CONCAT(SCORE),SUM(SCORE) FROM CC GROUP BY STUDENT;
3.使用Oracle 11g pivot方法
SELECT KIN.*,
KIN.a+KIN.b+KIN.c+KIN.d AS TOTAL
FROM
(SELECT *
FROM CC PIVOT ( MAX(SCORE) FOR COURSE IN ('语文' AS A , '数学' AS B, '英语' AS C,'物理' AS D) )
) KIN;
4.使用DECODE方法
SELECT
student,
MAX(decode(COURSE, '语文', SCORE)) A,
MAX(DECODE(COURSE, '数学', SCORE)) B,
MAX(DECODE(COURSE, '英语', SCORE)) C,
MAX(DECODE(COURSE, '物理', SCORE)) D,
SUM(SCORE) TOTAL
FROM
CC
GROUP BY
student;
方法一：wmsys.wm_concat(column)
介绍：其函数在Oracle 10g推出，在10g版本中，返回字符串类型，在11g版本中返回clob类型。括号里面的参数是列，而且可以是多个列的集合，也就是说在括号里面可以自由地用‘||’合并字符串。如下面的例子： Select u_id, wmsys.wm_concat(goods || '(' || num || '斤)' ) goods_sum from shopping group by u_id
方法二：listagg (column,[,]) within group (order by ) [over (partition by )]
介绍：其函数在Oracle 11g 版本中推出，对分组后的数据按照一定的排序进行字符串连接。其中，“[,]”表示字符串连接的分隔符，如果选择使用[over (partition by )]则会使其变成分析函数；
方法三：sys_connect_by_path(column,<分隔符>)
介绍：其函数在Oracle 9i 版本中推出，用来合并链路的字符串。注意的是其一定要和connect by子句合用！
第一个参数是形成树形式的字段，第二个参数是父级和其子级分隔显示用的分隔符。
oracle--25行转列，列转行
猜你喜欢
转载自zhyp29.iteye.com/blog/2303289
今日推荐
周排行