SQL statement to get column type

问题:

Is there a SQL statement that can return the type of a column in a table?

回答1:

Using SQL Server:

SELECT DATA_TYPE 
FROM INFORMATION_SCHEMA.COLUMNS
WHERE 
     TABLE_NAME = 'yourTableName' AND 
     COLUMN_NAME = 'yourColumnName'

回答2:

The easiest way in TSQL is:

SELECT COLUMN_NAME, DATA_TYPE 
FROM INFORMATION_SCHEMA.COLUMNS 
WHERE TABLE_NAME = 'yourTableName'

回答3:

For SQL Server, this system stored procedure will return all table information, including column datatypes:

exec sp_help YOURTABLENAME

回答4:

In TSQL/MSSQL it looks like:

SELECT t.name, c.name 
FROM sys.tables t 
JOIN sys.columns c ON t.object_id = c.object_id
JOIN sys.types y ON y.system_type_id = c.system_type_id
WHERE t.name = ''

回答5:

in oracle SQL you would do this:

SELECT
    DATA_TYPE
FROM
    all_tab_columns 
WHERE
    table_name = 'TABLE NAME' -- in uppercase
AND column_name = 'COLUMN NAME' -- in uppercase

回答6:

If you're using MySQL you could try

SHOW COLUMNS FROM `tbl_name`;

SHOW COLUMNS on dev.mysql.com

Otherwise you should be able to do

DESCRIBE `tbl_name`;

回答7:

Another variation using MS SQL:

SELECT TYPE_NAME(system_type_id) 
FROM sys.columns 
WHERE name = 'column_name'
AND [object_id] = OBJECT_ID('[dbo].[table_name]');

回答8:

USE [YourDatabaseName]
GO

SELECT column_name 'Column Name',
data_type 'Data Type'
FROM information_schema.columns
WHERE table_name = 'YourTableName'
GO

This will return the values Column Name, showing you the names of the columns, and the Data Types of those columns (ints, varchars, etc).

回答9:

For IBM DB2 :

SELECT TYPENAME FROM SYSCAT.COLUMNS WHERE TABSCHEMA='your_schema_name' AND TABNAME='your_table_name' AND COLNAME='your_column_name'

回答10:

Using TSQL/MSSQL

This query will get you: table name, column name, data type, data type length, and allowable nulls

SELECT TABLE_NAME,COLUMN_NAME, DATA_TYPE, CHARACTER_MAXIMUM_LENGTH, IS_NULLABLE
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'your_table_name'

The only thing that needs to be changed is your_table_name.

回答11:

In my case I needed to get the data type for Dynamic SQL (Shudder!) anyway here is a function that I created that returns the full data type. For example instead of returning 'decimal' it would return DECIMAL(18,4): dbo.GetLiteralDataType

回答12:

Use this query to get Schema, Table, Column,Type, max_length, is_nullable

SELECT QUOTENAME(SCHEMA_NAME(tb.[schema_id])) AS 'Schema'
    ,QUOTENAME(OBJECT_NAME(tb.[OBJECT_ID])) AS 'Table'
    ,C.NAME as 'Column'
    ,T.name AS 'Type'
    ,C.max_length
    ,C.is_nullable
FROM SYS.COLUMNS C INNER JOIN SYS.TABLES tb ON tb.[object_id] = C.[object_id]
    INNER JOIN SYS.TYPES T ON C.system_type_id = T.user_type_id
WHERE tb.[is_ms_shipped] = 0
ORDER BY tb.[Name]

回答13:

Using TSQL/MSSQL

You can use INTO keyword.

The result of SELECT into a real TABLE

Example: select .... INTO real_table_name

After

sp_help real_table_name

回答14:

For Spark SQL:

DESCRIBE [db_name.]table_name column_name

回答15:

For Apache Derby as shown in this answer:

select columndatatype from sys.syscolumns
  where referenceid = (
    select tableid from sys.systables
    where tablename = 'YOUR_TABEL_NAME'
    and columnname= 'YOUR_COLUMN_NAME')

回答16:

In vb60 you can do this:

Public Cn As ADODB.Connection
'open connection
Dim Rs As ADODB.Recordset
 Set Rs = Cn.OpenSchema(adSchemaColumns, Array(Empty, Empty, UCase("Table"), UCase("field")))

'and sample (valRs is my function for rs.fields("CHARACTER_MAXIMUM_LENGTH").value):

 RT_Charactar_Maximum_Length = (ValRS(Rs, "CHARACTER_MAXIMUM_LENGTH"))
        rt_Tipo = (ValRS(Rs, "DATA_TYPE"))

回答17:

To retrieve the actual declared data types, for example for use in dynamic SQL to ALTER COLUMNs, something like this can be used:

SELECT
    TABLE_NAME, 
    COLUMN_NAME,
    DATA_TYPE
        + CASE WHEN DATA_TYPE IN ('char','nchar','varchar','nvarchar','binary','varbinary')
                    AND CHARACTER_MAXIMUM_LENGTH > 0 THEN
                 COALESCE('('+CONVERT(varchar,CHARACTER_MAXIMUM_LENGTH)+')','')
            ELSE '' END
        + CASE WHEN DATA_TYPE IN ('decimal','numeric') THEN
                COALESCE('('+CONVERT(varchar,NUMERIC_PRECISION)+','+CONVERT(varchar,NUMERIC_SCALE)+')','')
            ELSE '' END
        AS Declaration_Type,
    CASE WHEN IS_NULLABLE='NO' THEN 'NOT ' ELSE '' END + 'NULL' AS Nullable
FROM INFORMATION_SCHEMA.COLUMNS
ORDER BY 1,2

回答18:

SHOW COLUMNS FROM //table_name// ;

It will give you information about all the columns from the table .