作业XD
真的想手写,而且Latex官方文档慢的一批。
直接放图和代码
- S ⋈ ∏ S N O ( σ P N O = P 1 ( S P ) ) S \bowtie \prod_{\tiny SNO} (\sigma_{\tiny PNO = P1}(SP)) S⋈∏SNO(σPNO=P1(SP))
- S ⋈ ∏ S N O ( S P ÷ ∏ P N O ( σ S N O = S 2 ( S P ) ) ) S \bowtie \prod_{\tiny SNO} (SP \div \prod_{\tiny PNO}(\sigma_{\tiny SNO = S2}(SP) )) S⋈∏SNO(SP÷∏PNO(σSNO=S2(SP)))
- S ⋈ ( ∏ S N O ( S P ) − ∏ S N O ( S P ÷ ∏ P N A M E ( σ P N A M E = P 2 ( S P ) ) ) − ∏ S N O ( S P ÷ ∏ P N A M E ( σ P N A M E = P 3 ( S P ) ) ) ) S \bowtie (\prod_{\tiny SNO}(SP)-\prod_{\tiny SNO}(SP \div \prod_{\tiny PNAME}(\sigma_{\tiny PNAME = P2}(SP)))-\prod_{\tiny SNO}(SP \div \prod_{\tiny PNAME}(\sigma_{\tiny PNAME = P3}(SP)))) S⋈(∏SNO(SP)−∏SNO(SP÷∏PNAME(σPNAME=P2(SP)))−∏SNO(SP÷∏PNAME(σPNAME=P3(SP))))
- S ⋈ ∏ S N O ( S P ÷ ( ∏ P N A M E ( σ P N A M E = P 1 ( S P ) ) ∪ ∏ P N A M E ( σ P N A M E = P 2 ( S P ) ) ) S\bowtie\prod_{\tiny SNO}(SP \div (\prod_{\tiny PNAME}(\sigma_{\tiny PNAME = P1}(SP)) \cup\prod_{\tiny PNAME}(\sigma_{\tiny PNAME = P2}(SP))) S⋈∏SNO(SP÷(∏PNAME(σPNAME=P1(SP))∪∏PNAME(σPNAME=P2(SP)))
- δ S N O , S N A M E → S N O ′ , S N A M E ′ ( σ S N A M E = S 1 ( S ) ) ⋈ S ⋈ S P ⋈ P \delta_{\tiny SNO,SNAME\rightarrow SNO^{'},SNAME^{'}}(\sigma_{\tiny SNAME=S1}(S)) \bowtie S \bowtie SP \bowtie P δSNO,SNAME→SNO′,SNAME′(σSNAME=S1(S))⋈S⋈SP⋈P
- ∏ S N O ( σ Q T Y > 1000 ( ∏ P N O ( σ C O L O R = R E D ( P ) ) ⋈ S P ) ) ⋈ S \prod_{\tiny SNO}(\sigma_{\tiny QTY > 1000}(\prod_{\tiny PNO}(\sigma_{\tiny COLOR=RED}(P)) \bowtie SP))\bowtie S ∏SNO(σQTY>1000(∏PNO(σCOLOR=RED(P))⋈SP))⋈S
1. $S \bowtie \prod_{\tiny SNO} (\sigma_{\tiny PNO = P1}(SP))$
2. $S \bowtie \prod_{\tiny SNO} (SP \div \prod_{\tiny PNO}(\sigma_{\tiny SNO = S2}(SP) ))$
3. $S \bowtie (\prod_{\tiny SNO}(SP)-\prod_{\tiny SNO}(SP \div \prod_{\tiny PNAME}(\sigma_{\tiny PNAME = P2}(SP)))-\prod_{\tiny SNO}(SP \div \prod_{\tiny PNAME}(\sigma_{\tiny PNAME = P3}(SP))))$
4. $S\bowtie\prod_{\tiny SNO}(SP \div (\prod_{\tiny PNAME}(\sigma_{\tiny PNAME = P1}(SP)) \cup\prod_{\tiny PNAME}(\sigma_{\tiny PNAME = P2}(SP)))$
5. $\delta_{\tiny SNO,SNAME\rightarrow SNO^{'},SNAME^{'}}(\sigma_{\tiny SNAME=S1}(S)) \bowtie S \bowtie SP \bowtie P$
6. $\prod_{\tiny SNO}(\sigma_{\tiny QTY > 1000}(\prod_{\tiny PNO}(\sigma_{\tiny COLOR=RED}(P)) \bowtie SP))\bowtie S$
Latex整理
- 连接
⋈
\bowtie
⋈
\bowtie
- 选择
σ
\sigma
σ
\sigma
- 投影
∏
\prod
∏
\prod
- 除
÷
\div
÷
\div
还有一堆写不完,挂个常用数学符号链接,希望别挂掉。
https://blog.youkuaiyun.com/Ying_Xu/article/details/51240291