Create a stored procedure in SQL Server that returns total count of columns in table and distinct count of values in each column

问题

I need a stored procedure that takes any table name as a parameter and returns total count of rows and distinct count of values in each column of that particular table when executed.

Let's take the sample table as below:

create table journey
(
    Src varchar(255),  
    Dest varchar(255)
)

insert into journey 
values ('Jaipur', 'Mumbai'), ('Mumbai', 'Jaipur'), ('Kolkata', 'Bangalore'), 
       ('Bangalore', 'Indore'),('Indore', 'Lucknow'), ('Lucknow', 'Indore')

Can anybody help me with this task of dynamic SQL.

I have made an attempt which is not giving the result. Can anybody suggest where the code is lagging

create procedure test @table_name varchar(255)
AS

BEGIN 

SELECT count(*) as [Number of columns]
FROM information_schema.columns
WHERE table_name = '@table_name'



 SELECT @table_name = 
     Replace( 
       'SELECT ' + SUBSTRING((SELECT ',' +'COUNT(DISTINCT(' + column_name + ')) As ' 
       + column_name + ' ' + CHAR(13) + CHAR(10) 
       FROM information_schema.columns 
       WHERE table_name = '@table_name' 
       for xml path('')),2,200000) + 'FROM @table_name','&#x0D;','')
 exec(@table_name)

END

exec test @table_name = "journey";

回答1:

This is an extension of something I wrote on SQL Server Central awhile ago, that includes a COUNT of both non-NULL and (optionally)DISTINCT values:

DECLARE @Schema sysname, @Table sysname, @IncDistinct bit = 1;
SET @Schema = 'dbo';
SET @Table = 'icp_yyclient';

DECLARE @SQL nvarchar(MAX)

SET @SQL = N'WITH Counts AS (' + NCHAR(13) + NCHAR(10) + 
           N'    SELECT @Schema AS SchemaName,' + NCHAR(13) + NCHAR(10) +
           N'           @Table AS TableName,' +
           STUFF((SELECT N',' + NCHAR(13) + NCHAR(10) + 
                           N'           COUNT(' + CASE WHEN C.DATA_TYPE IN ('text','image') THEN '1' ELSE QUOTENAME(C.COLUMN_NAME) END + N') AS ' + QUOTENAME(COLUMN_NAME) + N',' + NCHAR(13) + NCHAR(10) +
                           N'           COUNT(DISTINCT ' + CASE WHEN C.DATA_TYPE IN ('text','image') THEN '1' ELSE QUOTENAME(C.COLUMN_NAME) END + N') AS ' + QUOTENAME(COLUMN_NAME + N'_Distinct')
                   FROM INFORMATION_SCHEMA.COLUMNS C
                   WHERE C.TABLE_SCHEMA = @Schema
                       AND C.TABLE_NAME = @Table
                       --AND C.DATA_TYPE NOT IN ('text','image')
                   ORDER BY C.ORDINAL_POSITION
                   FOR XML PATH(N''),TYPE).value('.','nvarchar(MAX)'),1,14,N'') + NCHAR(13) + NCHAR(10) + 
           N'    FROM ' + QUOTENAME(@Schema) + N'.' + QUOTENAME(@Table) + N')' + NCHAR(13) + NCHAR(10) + 
           N'SELECT V.OrdinalPosition,' + NCHAR(13) + NCHAR(10) + 
           N'       V.ColumnName,' + NCHAR(13) + NCHAR(10) + 
           N'       V.NonNullCount,' + NCHAR(13) + NCHAR(10) + 
           CASE WHEN @IncDistinct = 1 THEN N'       V.DistinctCount,' + NCHAR(13) + NCHAR(10) ELSE N'' END +
           N'       ISC.DATA_TYPE + ISNULL(NULLIF(DT.S,''(*)''),'''') AS Datatype,' + NCHAR(13) + NCHAR(10) +
           N'       K.KeyType' + NCHAR(13) + NCHAR(10) +
           N'FROM Counts C' + NCHAR(13) + NCHAR(10) + 
           N'     CROSS APPLY(VALUES' + STUFF((SELECT N',' + NCHAR(13) + NCHAR(10) + 
                                                       N'                       (' + CONVERT(varchar(4),C.ORDINAL_POSITION) +N',N' + QUOTENAME(C.COLUMN_NAME,'''') + N',C.' + QUOTENAME(C.COLUMN_NAME) + N',C.' + QUOTENAME(C.COLUMN_NAME + N'_Distinct') + N')'
                                               FROM INFORMATION_SCHEMA.COLUMNS C
                                               WHERE C.TABLE_NAME = @Table
                                                 --AND C.DATA_TYPE NOT IN ('text','image')
                                               ORDER BY C.ORDINAL_POSITION
                                               FOR XML PATH(N''),TYPE).value('.','nvarchar(MAX)'),1,26,N'') + N')V(OrdinalPosition,ColumnName,NonNullCount,DistinctCount)' + NCHAR(13) + NCHAR(10) +
           N'     JOIN INFORMATION_SCHEMA.COLUMNS ISC ON C.SchemaName = ISC.TABLE_SCHEMA' + NCHAR(13) + NCHAR(10) +
           N'                                        AND C.TableName = ISC.TABLE_NAME' + NCHAR(13) + NCHAR(10) +
           N'                                        AND V.ColumnName = ISC.COLUMN_NAME' + NCHAR(13) + NCHAR(10) + 
           N'     CROSS APPLY (VALUES(''('' + STUFF(CONCAT('','' + CASE ISC.CHARACTER_MAXIMUM_LENGTH WHEN -1 THEN ''MAX'' ELSE CONVERT(varchar(4),ISC.CHARACTER_MAXIMUM_LENGTH) END,' + NCHAR(13) + NCHAR(10)+
           N'                                            '','' + CASE WHEN ISC.DATA_TYPE NOT LIKE ''%int'' THEN CONVERT(varchar(4),ISC.NUMERIC_PRECISION) END,' + NCHAR(13) + NCHAR(10) +
           N'                                            '','' + CASE WHEN ISC.DATA_TYPE NOT LIKE ''%int'' THEN CONVERT(varchar(4),ISC.NUMERIC_SCALE) END,' + NCHAR(13) + NCHAR(10) +
           N'                                            '','' + CASE WHEN ISC.DATA_TYPE NOT IN (''datetime'',''smalldatetime'') THEN CONVERT(varchar(4),ISC.DATETIME_PRECISION) END),1,1,'''') + '')'')) DT(S)' + NCHAR(13) + NCHAR(10) +
           N'     OUTER APPLY(SELECT TC.CONSTRAINT_TYPE AS KeyType ' + NCHAR(13) + NCHAR(10) + 
           N'                 FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS TC' + NCHAR(13) + NCHAR(10) + 
           N'                      JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE KCU ON TC.TABLE_SCHEMA = KCU.TABLE_SCHEMA' + NCHAR(13) + NCHAR(10) + 
           N'                                                                  AND TC.TABLE_NAME = KCU.TABLE_NAME' + NCHAR(13) + NCHAR(10) + 
           N'                                                                  AND TC.CONSTRAINT_NAME = KCU.CONSTRAINT_NAME' + NCHAR(13) + NCHAR(10) + 
           N'                 WHERE KCU.COLUMN_NAME = V.ColumnName' + NCHAR(13) + NCHAR(10) + 
           N'                   AND TC.TABLE_SCHEMA = ISC.TABLE_SCHEMA' + NCHAR(13) + NCHAR(10) + 
           N'                   AND TC.TABLE_NAME = ISC.TABLE_NAME) K' + NCHAR(13) + NCHAR(10) +
           N'ORDER BY V.OrdinalPosition';

PRINT @SQL; --you will need to use the SELECT here if @SQL is over 4,000 characters
--SELECT @SQL;
EXEC sp_executesql @SQL, N'@Schema sysname,@Table sysname',@Schema = @Schema, @Table = @Table;

来源：https://stackoverflow.com/questions/60654478/create-a-stored-procedure-in-sql-server-that-returns-total-count-of-columns-in-t

标签

sql-server

tsql

stored-procedures

dynamic-sql