是否有SQL语句可以返回表中列的类型?


当前回答

在TSQL/MSSQL中,它看起来像:

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.user_type_id = c.user_type_id
WHERE t.name = ''

其他回答

由于有些人要求数据类型的精度,我想分享我为此目的而创建的脚本。

SELECT TABLE_NAME As 'TableName'
       COLUMN_NAME As 'ColumnName'
       CONCAT(DATA_TYPE, '(', COALESCE(CHARACTER_MAXIMUM_LENGTH, NUMERIC_PRECISION, DATETIME_PRECISION, ''), IIF(NUMERIC_SCALE <> 0, CONCAT(', ', NUMERIC_SCALE), ''), ')', IIF(IS_NULLABLE = 'YES', ', null', ', not null')) As 'ColumnType'
FROM INFORMATION_SCHEMA.COLUMNS
WHERE -- ...
ORDER BY 'TableName', 'ColumnName'

这并不完美,但在大多数情况下都有效。

使用sql server

要检索实际声明的数据类型,例如在动态SQL To ALTER COLUMNs中使用,可以使用这样的方法:

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

我认为在Microsoft SQL Server Management Studio中最简单和最有用的方法是:

EXEC [ServerName].[DatabaseName].dbo.sp_help 'TableName'

我发现这对查询很有用,特别是如果他们使用聚合或几个表(SQL Server)

DECLARE @query nvarchar(max) = 'select * from yourtable';
EXEC sp_describe_first_result_set @query, null, 0; 

使用这个查询

SELECT * FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'TABLE_NAME'
ORDER BY ORDINAL_POSITION