Oracle 自动生成merge into 语法

create or replace function dev_merge(p_table_name varchar2, v_java number:=0) return clob

as

v_is_pk pls_integer:=0;

v_sql_total clob; v_sql_join clob;

v_sql_param clob;

v_sql_update clob;

v_sql_query clob;

v_sql_insert clob;

begin

select count(*) into v_is_pk

from user_cons_columns cu inner

join user_constraints au on cu.constraint_name = au.constraint_name and au.constraint_type = 'P'

where au.table_name = upper(p_table_name);

if v_is_pk=0 then

　　return '此表没有主键，无法生成！';

end if;

--循环所有字段

for dj in (select lower(a.column_name) column_name from user_tab_columns a where a.table_name=upper(p_table_name) order by a.column_id) loop

--获取主键

select count(*) into v_is_pk

from user_cons_columns cu

inner join user_constraints au on cu.constraint_name = au.constraint_name and au.constraint_type = 'P'

where au.table_name = upper(p_table_name) and cu.column_name=upper(dj.column_name);

--关联语句

if v_is_pk=1then

　　v_sql_join:=v_sql_join||' and a.'||dj.column_name||'=b.'||dj.column_name;

end if;

--参数语句

if v_java=0 then

　　v_sql_param:=v_sql_param||', :'||dj.column_name||' as '||dj.column_name;

else

　　v_sql_param:=v_sql_param||', ? as '||dj.column_name;

end if;

if v_is_pk=0 then

--更新语句

　　v_sql_update:=v_sql_update||' ,a.'||dj.column_name||'=b.'||dj.column_name||chr(10);

end if;

--插入语句

v_sql_query:=v_sql_query||' ,'||dj.column_name;

v_sql_insert:=v_sql_insert||' ,b.'||dj.column_name;

end loop;

dbms_output.put_line(v_sql_param);

v_sql_total:=v_sql_total||chr(10)||chr(10);

v_sql_total:=v_sql_total||'merge into '|| p_table_name ||' a '||chr(10);

v_sql_total:=v_sql_total||'using (select '|| substr(v_sql_param,3) ||' from dual) b '||chr(10);

v_sql_total:=v_sql_total||'on ('||substr(v_sql_join,6)||')'||chr(10);

v_sql_total:=v_sql_total||'when matched then update set'||chr(10);

v_sql_total:=v_sql_total||' '||substr(v_sql_update,4);

v_sql_total:=v_sql_total||'when not matched then'||chr(10);

v_sql_total:=v_sql_total||' insert('||substr(v_sql_query,3)||')'||chr(10);

v_sql_total:=v_sql_total||' values('||substr(v_sql_insert,3)||')'||chr(10)||chr(10);

return v_sql_total;

end;

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最后，我们只需要把表名套进去就OK了！

select dev_merge('表名','1') from dual