领测软件测试网
软件测试技术门户x'uI:|#JIhK8BL:ut3R;Rj4{ 例2:
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W(H\%YZ6_UF*k#CA%a} Sn3DVy SQL> SELECT last_name
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U.Q]%Yn p+v*_F)xV[ 2 FROM s_emp
软件测试技术门户CB2Jp9m*c1@软件测试技术门户A3mR:}$s(Z| 3 WHERE last_name LIKE ’_a%’; //显示所有第二个字母为 a的last_name
E;`9@(wq软件测试技术门户E!D#_aXo-v6f 例3:
软件测试技术门户 mI%gI&|*N0h0v'aZ 如果有列为NULL
L'v}nb?g3biddaL.L8v)It SQL> SELECT id, name, credit_rating
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e-e 2 FROM s_customer
软件测试技术门户'J6J%]7C-t'u+['[#f;p;U
E$S$O 3 WHERE sales_rep_id IS NULL;
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|9rm"K 优先级:
0V"`)M;X5Gu\Ws oP7F Order Evaluated Operator
软件测试技术门户]4~(Ylvk1J}&i+} l9} 1 All comparison operators (=, <>, >, >=, <, <=, IN, LIKE, IS NULL, BETWEEN)
8L)[4i}e$t|0GA软件测试技术门户.XkT/e6a_k2bQ软件测试技术门户'M8L2[-Wj2E