Sql 查询以查找包括null在内的所有db参数值

此查询是否获取表中参数不可用的所有值（包括null）

select name,display_value 
from v$spparameter where nvl(name,'null') in(
    'memory_target','sga_target','pga_aggregate_target','pga_aggregate_limit','db_cache_size',
    'shared_pool_size','large_pool_size','result_cache_max_size','processes',
    'session_cached_cursors','open_cursors','db_securefile','cpu_count',
    'parallel_max_servers','job_queue_processes','log_buffer','_b_tree_bitmap_plans',
    'use_large_pages','audit_trail','nls_sort','plsql_code_type','resource_manager_plan',
    'shared_servers','max_shared_servers','dispatchers','event','undo_retention',
    '_highthreshold_undoretention','parallel_adaptive_multi_user','parallel_force_local',
    'db_files','db_performance_profile','_srvntfn_max_concurrent_jobs',
    '_optimizer_use_feedback','optimizer_dsdir_usage_control',
    '_sql_plan_directive_mgmt_control','_fix_control','global_txn_processes',
    '_disable_autotune_gtx', '_ges_server_processes','sga_max_size',
    '_securefiles_concurrency_estimate','streams_pool_size')
order by name;

---

您可以尝试在where caluse中添加

或name为null

因为SQL

NULL

不是一个值。您需要使用

IS NULL

来获取它

---

您可以尝试在where caluse中添加

或name为null

因为SQL

NULL

不是一个值。您需要使用

IS NULL

来获取它

---

差不多。您正在将null值转换为字符串“null”，但忘记将其包含在“in”列表中。只需在列表中添加“null”

select name,display_value 
from v$spparameter where nvl(name,'null') in('null',
    'memory_target','sga_target','pga_aggregate_target','pga_aggregate_limit','db_cache_size',
    'shared_pool_size','large_pool_size','result_cache_max_size','processes',
    'session_cached_cursors','open_cursors','db_securefile','cpu_count',
    'parallel_max_servers','job_queue_processes','log_buffer','_b_tree_bitmap_plans',
    'use_large_pages','audit_trail','nls_sort','plsql_code_type','resource_manager_plan',
    'shared_servers','max_shared_servers','dispatchers','event','undo_retention',
    '_highthreshold_undoretention','parallel_adaptive_multi_user','parallel_force_local',
    'db_files','db_performance_profile','_srvntfn_max_concurrent_jobs',
    '_optimizer_use_feedback','optimizer_dsdir_usage_control',
    '_sql_plan_directive_mgmt_control','_fix_control','global_txn_processes',
    '_disable_autotune_gtx', '_ges_server_processes','sga_max_size',
    '_securefiles_concurrency_estimate','streams_pool_size')
order by name;

---

差不多。您正在将null值转换为字符串“null”，但忘记将其包含在“in”列表中。只需在列表中添加“null”

select name,display_value 
from v$spparameter where nvl(name,'null') in('null',
    'memory_target','sga_target','pga_aggregate_target','pga_aggregate_limit','db_cache_size',
    'shared_pool_size','large_pool_size','result_cache_max_size','processes',
    'session_cached_cursors','open_cursors','db_securefile','cpu_count',
    'parallel_max_servers','job_queue_processes','log_buffer','_b_tree_bitmap_plans',
    'use_large_pages','audit_trail','nls_sort','plsql_code_type','resource_manager_plan',
    'shared_servers','max_shared_servers','dispatchers','event','undo_retention',
    '_highthreshold_undoretention','parallel_adaptive_multi_user','parallel_force_local',
    'db_files','db_performance_profile','_srvntfn_max_concurrent_jobs',
    '_optimizer_use_feedback','optimizer_dsdir_usage_control',
    '_sql_plan_directive_mgmt_control','_fix_control','global_txn_processes',
    '_disable_autotune_gtx', '_ges_server_processes','sga_max_size',
    '_securefiles_concurrency_estimate','streams_pool_size')
order by name;

既然nvl（名称，'null'）将空值转换为字符串

'null'

，为什么不将

'null'

添加到列表中呢<代码>…在（'null'、'memory\u target'、'sga\u target'、…）中nvl（名称，'null'）的位置…您使用的是哪种dbms？（

NVL（）

不是ANSI SQL。）既然NVL（名称，'null'）将null转换为字符串

'null'

，为什么不将

'null'

添加到列表中呢<代码>…在（'null'、'memory\u target'、'sga\u target'、…）中nvl（名称，'null'）的位置…您使用的是哪种dbms？（

NVL（）

不是ANSI SQL。）