informix日期函数_informix_informix rownum

查询登陆帐户的用户名称

SELECT * FROM cust_calls WHERE user_id = USER

查询当前日期

SELECT * FROM orders WHERE order_date = TODAY

主机的服务器名称

SELECT FIRST 1 DBINFO(’dbhostname’) FROM systables

SELECT name, NVL(address, "address is unknown") AS address ROM student

LEFT JOIN， LEFT OUTER JOIN，RIGHT JOIN 和 RIGHT OUTER JOIN 与on 的连接

SELECT c.customer_num, c.lname, c.company, c.phone,

u.call_dtime, u.call_descr

FROM customer c LEFT OUTER JOIN cust_calls u

ON c.customer_num = u.customer_num；

SELECT *

FROM (t1 LEFT OUTER JOIN (t2 LEFT OUTER JOIN t3 ON t2.c1=t3.c1)

ON t1.c1=t3.c1) JOIN (t4 LEFT OUTER JOIN t5 ON t4.c1=t5.c1)

ON t1.c1=t4.c1;

SELECT *

FROM (t1 LEFT OUTER JOIN (t2 LEFT OUTER JOIN t3 ON t2.c1=t3.c1)

ON t1.c1=t3.c1),

(t4 LEFT OUTER JOIN t5 ON t4.c1=t5.c1)

WHERE t1.c1 = t4.c1;

SELECT *

FROM (t1 LEFT OUTER JOIN (t2 LEFT OUTER JOIN t3 ON t2.c1=t3.c1)

ON t1.c1=t3.c1) LEFT OUTER JOIN (t4 JOIN t5 ON t4.c1=t5.c1)

ON t1.c1=t4.c1;

SELECT *

FROM t1 LEFT OUTER JOIN (t2 LEFT OUTER JOIN t3 ON t2.c1=t3.c1)

ON t1.c1=t2.c1;

SELECT *

FROM t1 LEFT OUTER JOIN (t2 LEFT OUTER JOIN t3 ON t2.c1=t3.c1)

ON t1.c1=t3.c1;

SELECT *

FROM (t1 LEFT OUTER JOIN t2 ON t1.c1=t2.c1)

LEFT OUTER JOIN t3 ON t2.c1=t3.c1;

SELECT *

FROM (t1 LEFT OUTER JOIN t2 ON t1.c1=t2.c1)

LEFT OUTER JOIN t3 ON t1.c1=t3.c1;

SELECT *

FROM t9, (t1 LEFT JOIN t2 ON t1.c1=t2.c1) ,

(t3 LEFT JOIN t4 ON t3.c1=10), t10, t11 ,

(t12 LEFT JOIN t14 ON t12.c1=100);

//满足所有的相等 且 右边有值条件的结果

SELECT c.customer_num, c.fname, c.lname, o.order_num,

o.order_date, o.customer_num

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