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'AS' clauses for expression columns may be omitted
author Adam Chlipala <adamc@hcoop.net>
date Thu, 25 Mar 2010 16:41:51 -0400
parents 1da49fd79e20
children b52929351402
comparison
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1193:1da49fd79e20 1194:601a77af0477
1957 $$\begin{array}{rrcll} 1957 $$\begin{array}{rrcll}
1958 \textrm{Projections} & P &::=& \ast & \textrm{all columns} \\ 1958 \textrm{Projections} & P &::=& \ast & \textrm{all columns} \\
1959 &&& p,^+ & \textrm{particular columns} \\ 1959 &&& p,^+ & \textrm{particular columns} \\
1960 \textrm{Pre-projections} & p &::=& t.f & \textrm{one column from a table} \\ 1960 \textrm{Pre-projections} & p &::=& t.f & \textrm{one column from a table} \\
1961 &&& t.\{\{c\}\} & \textrm{a record of columns from a table (of kind $\{\mt{Type}\}$)} \\ 1961 &&& t.\{\{c\}\} & \textrm{a record of columns from a table (of kind $\{\mt{Type}\}$)} \\
1962 &&& E \; [\mt{AS} \; f] & \textrm{expression column} \\
1962 \textrm{Table names} & t &::=& x & \textrm{constant table name (automatically capitalized)} \\ 1963 \textrm{Table names} & t &::=& x & \textrm{constant table name (automatically capitalized)} \\
1963 &&& X & \textrm{constant table name} \\ 1964 &&& X & \textrm{constant table name} \\
1964 &&& \{\{c\}\} & \textrm{computed table name (of kind $\mt{Name}$)} \\ 1965 &&& \{\{c\}\} & \textrm{computed table name (of kind $\mt{Name}$)} \\
1965 \textrm{Column names} & f &::=& X & \textrm{constant column name} \\ 1966 \textrm{Column names} & f &::=& X & \textrm{constant column name} \\
1966 &&& \{c\} & \textrm{computed column name (of kind $\mt{Name}$)} \\ 1967 &&& \{c\} & \textrm{computed column name (of kind $\mt{Name}$)} \\
1995 \textrm{SQL integer} & N &::=& n \mid \{e\} \\ 1996 \textrm{SQL integer} & N &::=& n \mid \{e\} \\
1996 \end{array}$$ 1997 \end{array}$$
1997 1998
1998 Additionally, an SQL expression may be inserted into normal Ur code with the syntax $(\mt{SQL} \; E)$ or $(\mt{WHERE} \; E)$. Similar shorthands exist for other nonterminals, with the prefix $\mt{FROM}$ for $\mt{FROM}$ items and $\mt{SELECT1}$ for pre-queries. 1999 Additionally, an SQL expression may be inserted into normal Ur code with the syntax $(\mt{SQL} \; E)$ or $(\mt{WHERE} \; E)$. Similar shorthands exist for other nonterminals, with the prefix $\mt{FROM}$ for $\mt{FROM}$ items and $\mt{SELECT1}$ for pre-queries.
1999 2000
2001 Unnamed expression columns in $\mt{SELECT}$ clauses are assigned consecutive natural numbers, starting with 1.
2002
2000 \subsubsection{DML} 2003 \subsubsection{DML}
2001 2004
2002 DML commands $D$ are added to the rules for expressions $e$. 2005 DML commands $D$ are added to the rules for expressions $e$.
2003 2006
2004 $$\begin{array}{rrcll} 2007 $$\begin{array}{rrcll}