mysql怎么查看表結構及已有索引信息

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查看表結構及已有索引信息

需求背景是給一個表名然后給出相應的表結構信息及索引信息

常用的命令有如下：

desc tableName; desc employees.employees;
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show columns from tableName; show COLUMNS from employees.employees;

describe tableName; DESCRIBE employees.employees;

這三個顯示的結果都是一樣的，顯示表中 filed，type，null，key，default 及 extra。

show create table tableName; show CREATE TABLE employees.employees;

這個語句會顯示這個表的建表語句。

select * from columns where table_name= 表名
select * from information_schema.COLUMNS where TABLE_SCHEMA= employees and TABLE_NAME= employees

這個顯示的結果就比較全了。

接下來，來點更全的 sql，這個是用來同步 mysql 和 orac 數據字典的所有 sql。

mysql 部分：

01
## 查看所有的庫
02
SELECT
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lower(schema_name) schema_name
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FROM
05
information_schema.schemata
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WHERE
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schema_name NOT IN (
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mysql ,
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information_schema ,
10
test ,
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search ,
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tbsearch ,
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sbtest ,
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dev_ddl
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)
16

17
## 產看某一個庫中的所有表
18
SELECT
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table_name,
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create_time updated_at,
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table_type,
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ENGINE,
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table_rows num_rows,
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table_comment,
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ceil(data_length / 1024 / 1024) store_capacity
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FROM
27
information_schema.TABLES
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WHERE
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table_schema = employees
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AND table_name NOT LIKE tmp#_% ESCAPE #
31

32
## 查看某一個庫下某一個表的所有字段
33
SELECT
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lower(column_name) column_name,
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ordinal_position position,
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column_default dafault_value,
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substring(is_nullable, 1, 1) nullable,
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column_type data_type,
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column_comment,
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character_maximum_length data_length,
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numeric_precision data_precision,
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numeric_scale data_scale
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FROM
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information_schema.COLUMNS
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WHERE
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table_schema = employees
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AND table_name = employees
48

49

50
## 查看某一個庫下某一張表的索引
51

52
SELECT DISTINCT
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lower(index_name) index_name,
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lower(index_type) type
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FROM
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information_schema.statistics
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WHERE
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table_schema = employees
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AND table_name = employees
60

61
## 查看某一個庫下某一張表的某一個索引
62

63
SELECT
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lower(column_name) column_name,
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seq_in_index column_position
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FROM
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information_schema.statistics
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WHERE
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table_schema = employees
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AND table_name = employees
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AND index_name = primary
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73
## 查看某一個庫下某一個表的注釋
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SELECT
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table_comment comments
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FROM
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information_schema.TABLES
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WHERE
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table_schema = employees
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AND table_name = employees
81

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## 查看某一個庫下某一個表的列的注釋
83
SELECT
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lower(column_name) column_name,
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column_comment comments
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FROM
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COLUMNS
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WHERE
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table_schema = employees
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AND table_name = employees
oracle 部分：
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001
#table structure:
002
SELECT
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lower(table_name) table_name,
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TEMPORARY,
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tablespace_name,
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num_rows,
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duration,
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ORACLE table_type,
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partitioned,
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(
011
SELECT
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ceil(sum(bytes) / 1024 / 1024)
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FROM
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dba_segments b
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WHERE
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a. OWNER = b. OWNER
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AND a.table_name = b.segment_name
018
) AS store_capacity
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FROM
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dba_tables a
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WHERE
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OWNER = ?
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AND table_name NOT LIKE TMP%
024

025
SELECT
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lower(column_name) column_name,
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column_id position,
028
data_type,
029
data_length,
030
data_precision,
031
data_scale,
032
nullable,
033
data_default default_value,
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default_length
035
FROM
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dba_tab_columns
037
WHERE
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OWNER = ?
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AND table_name = ?;
040

041
# index
042
SELECT
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lower(index_name) index_name,
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index_type type
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FROM
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dba_indexes
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WHERE
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OWNER = ?
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AND table_name = ?
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AND index_name NOT LIKE SYS_IL%
051

052
SELECT
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lower(column_name) column_name,
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column_position,
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descend
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FROM
057
dba_ind_columns
058
WHERE
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table_owner = ?
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AND table_name = ?
061
AND index_name = ?;
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063
#collect description
064
SELECT
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comments
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FROM
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dba_tab_comments
068
WHERE
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OWNER = ?
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AND table_name = ?;
071

072
SELECT
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lower(column_name) column_name,
074
comments
075
FROM
076
dba_col_comments
077
WHERE
078
OWNER = ?
079
AND table_name = ?;
080

081
#database
082
SELECT
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lower(username) username
084
FROM
085
dba_users
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WHERE
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username NOT IN (
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STDBYPERF ,
089
READONLY ,
090
APPQOSSYS ,
091
ANYSQL ,
092
DBFLASH ,
093
SYS ,
094
SYSTEM ,
095
MONITOR ,
096
TBSEARCH ,
097
MANAGER ,
098 www.2cto.com
SYSMAN ,
099
EXFSYS ,
100
WMSYS ,
101
DIP ,
102
TSMSYS ,
103
ORACLE_OCM ,
104
OUTLN ,
105
DBSNMP ,
106
PERFSTAT ,
107
SEARCH ,
108
TOOLS ,
109
TBDUMP ,
110
DMSYS ,
111
XDB ,
112
ANONYMOUS ,
113
DEV_DDL
114
);
115

116
#segsize
117
SELECT
118
round(sum(bytes) / 1024 / 1024, 0) mbytes
119
FROM
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dba_segments
121
WHERE
122
OWNER = ?
123
AND segment_name = ?;
關于 oralce 中的 segements，可以參考一下這個系列文章。