收集统计信息迁移

COLLECT STAT在Teradata中采集优化器统计信息，用于查询性能。DWS使用ANALYZE语句来支持COLLECT STAT。

详情请参见ANALYZE。

输入：COLLECT STATISTICS

COLLECT STAT tab1 COLUMN (c1, c2);	

输出

ANALYZE tab1 (c1, c2);

输入：COLLECT STATISTICS

COLLECT STATISTICS
  COLUMN (customer_id,customer_name) 
, COLUMN (postal_code) 
, COLUMN (customer_address) 
ON customer_t;

输出

ANALYZE customer_t (
     customer_id
     ,customer_name
     ,postal_code
     ,customer_address
)
;

输入：COLLECT STATISTICS（指定COLUMN）

COLLECT STATISTICS
  COLUMN (
  Order_Date
  -- ,o_orderID
/*COLLECT 
STATISTICS*/
  ,Order_ID
     )  
ON order_t;

输出

ANALYZE order_t (
    Order_Date
     ,Order_ID
)
;

输入：COLLECT STATISTICS（指定SchemaName）

COLLECT STATS COLUMN (
     empno
     ,ename
)
     ON ${schemaname}."usrTab1"
;

输出

ANALYZE ${schemaname}."usrTab1" 
(
     empno
     ,ename
)
;