Indexes for LIKE and ~, !~ operations.
This commit is contained in:
Bruce Momjian
parent
0308f91cd2
commit
1e7ba76e43
@ -10,7 +10,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 1.60 1997/10/30 16:39:27 thomas Exp $
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* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 1.61 1997/10/31 00:50:39 momjian Exp $
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*
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* HISTORY
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* AUTHOR DATE MAJOR EVENT
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@ -64,6 +64,7 @@ static Node *makeA_Expr(int oper, char *opname, Node *lexpr, Node *rexpr);
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static List *makeConstantList( A_Const *node);
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static char *FlattenStringList(List *list);
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static char *fmtId(char *rawid);
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static Node *makeIndexable(char *opname, Node *lexpr, Node *rexpr);
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/* old versions of flex define this as a macro */
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#if defined(yywrap)
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@ -2755,9 +2756,9 @@ a_expr: attr opt_indirection
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| '(' a_expr_or_null ')'
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{ $$ = $2; }
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| a_expr Op a_expr
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{ $$ = makeA_Expr(OP, $2, $1, $3); }
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{ $$ = makeIndexable($2,$1,$3); }
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| a_expr LIKE a_expr
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{ $$ = makeA_Expr(OP, "~~", $1, $3); }
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{ $$ = makeIndexable("~~", $1, $3); }
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| a_expr NOT LIKE a_expr
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{ $$ = makeA_Expr(OP, "!~~", $1, $4); }
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| Op a_expr
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@ -3527,6 +3528,176 @@ static Node *makeA_Expr(int oper, char *opname, Node *lexpr, Node *rexpr)
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return (Node *)a;
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}
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static Node *makeIndexable(char *opname, Node *lexpr, Node *rexpr)
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{
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Node *result = NULL;
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/* we do this so indexes can be used */
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if (strcmp(opname,"~") == 0)
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{
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if (nodeTag(rexpr) == T_A_Const &&
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((A_Const *)rexpr)->val.type == T_String &&
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((A_Const *)rexpr)->val.val.str[0] == '^')
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{
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A_Const *n = (A_Const *)rexpr;
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char *match_least = palloc(strlen(n->val.val.str)+2);
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char *match_most = palloc(strlen(n->val.val.str)+2);
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int pos, match_pos=0;
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/* skip leading ^ */
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for (pos = 1; n->val.val.str[pos]; pos++)
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{
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if (n->val.val.str[pos] == '.' ||
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n->val.val.str[pos] == '?' ||
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n->val.val.str[pos] == '*' ||
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n->val.val.str[pos] == '[' ||
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n->val.val.str[pos] == '$')
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break;
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if (n->val.val.str[pos] == '\\')
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pos++;
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match_least[match_pos] = n->val.val.str[pos];
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match_most[match_pos++] = n->val.val.str[pos];
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}
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if (match_pos != 0)
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{
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A_Const *least = makeNode(A_Const);
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A_Const *most = makeNode(A_Const);
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/* make strings to be used in index use */
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match_least[match_pos] = '\0';
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match_most[match_pos] = '\377';
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match_most[match_pos+1] = '\0';
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least->val.type = T_String;
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least->val.val.str = match_least;
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most->val.type = T_String;
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most->val.val.str = match_most;
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result = makeA_Expr(AND, NULL,
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makeA_Expr(OP, "~", lexpr, rexpr),
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makeA_Expr(AND, NULL,
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makeA_Expr(OP, ">=", lexpr, (Node *)least),
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makeA_Expr(OP, "<=", lexpr, (Node *)most)));
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}
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}
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}
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else if (strcmp(opname,"~*") == 0)
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{
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if (nodeTag(rexpr) == T_A_Const &&
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((A_Const *)rexpr)->val.type == T_String &&
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((A_Const *)rexpr)->val.val.str[0] == '^')
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{
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A_Const *n = (A_Const *)rexpr;
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char *match_lower_least = palloc(strlen(n->val.val.str)+2);
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char *match_lower_most = palloc(strlen(n->val.val.str)+2);
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char *match_upper_least = palloc(strlen(n->val.val.str)+2);
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char *match_upper_most = palloc(strlen(n->val.val.str)+2);
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int pos, match_pos=0;
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/* skip leading ^ */
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for (pos = 1; n->val.val.str[pos]; pos++)
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{
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if (n->val.val.str[pos] == '.' ||
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n->val.val.str[pos] == '?' ||
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n->val.val.str[pos] == '*' ||
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n->val.val.str[pos] == '[' ||
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n->val.val.str[pos] == '$')
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break;
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if (n->val.val.str[pos] == '\\')
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pos++;
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/* If we have punctuation, this works well */
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match_lower_least[match_pos] = tolower(n->val.val.str[pos]);
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match_lower_most[match_pos] = tolower(n->val.val.str[pos]);
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match_upper_least[match_pos] = toupper(n->val.val.str[pos]);
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match_upper_most[match_pos++] = toupper(n->val.val.str[pos]);
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}
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if (match_pos != 0)
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{
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A_Const *lower_least = makeNode(A_Const);
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A_Const *lower_most = makeNode(A_Const);
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A_Const *upper_least = makeNode(A_Const);
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A_Const *upper_most = makeNode(A_Const);
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/* make strings to be used in index use */
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match_lower_least[match_pos] = '\0';
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match_lower_most[match_pos] = '\377';
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match_lower_most[match_pos+1] = '\0';
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match_upper_least[match_pos] = '\0';
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match_upper_most[match_pos] = '\377';
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match_upper_most[match_pos+1] = '\0';
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lower_least->val.type = T_String;
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lower_least->val.val.str = match_lower_least;
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lower_most->val.type = T_String;
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lower_most->val.val.str = match_lower_most;
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upper_least->val.type = T_String;
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upper_least->val.val.str = match_upper_least;
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upper_most->val.type = T_String;
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upper_most->val.val.str = match_upper_most;
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result = makeA_Expr(AND, NULL,
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makeA_Expr(OP, "~*", lexpr, rexpr),
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makeA_Expr(OR, NULL,
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makeA_Expr(AND, NULL,
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makeA_Expr(OP, ">=", lexpr, (Node *)lower_least),
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makeA_Expr(OP, "<=", lexpr, (Node *)lower_most)),
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makeA_Expr(AND, NULL,
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makeA_Expr(OP, ">=", lexpr, (Node *)upper_least),
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makeA_Expr(OP, "<=", lexpr, (Node *)upper_most))));
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}
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}
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}
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else if (strcmp(opname,"~~") == 0)
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{
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if (nodeTag(rexpr) == T_A_Const &&
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((A_Const *)rexpr)->val.type == T_String)
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{
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A_Const *n = (A_Const *)rexpr;
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char *match_least = palloc(strlen(n->val.val.str)+2);
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char *match_most = palloc(strlen(n->val.val.str)+2);
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int pos, match_pos=0;
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for (pos = 0; n->val.val.str[pos]; pos++)
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{
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if ((n->val.val.str[pos] == '%' &&
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n->val.val.str[pos+1] != '%') ||
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(n->val.val.str[pos] == '_' &&
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n->val.val.str[pos+1] != '_'))
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break;
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if (n->val.val.str[pos] == '%' ||
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n->val.val.str[pos] == '_' ||
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n->val.val.str[pos] == '\\')
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pos++;
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match_least[match_pos] = n->val.val.str[pos];
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match_most[match_pos++] = n->val.val.str[pos];
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}
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if (match_pos != 0)
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{
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A_Const *least = makeNode(A_Const);
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A_Const *most = makeNode(A_Const);
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/* make strings to be used in index use */
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match_least[match_pos] = '\0';
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match_most[match_pos] = '\377';
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match_most[match_pos+1] = '\0';
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least->val.type = T_String;
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least->val.val.str = match_least;
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most->val.type = T_String;
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most->val.val.str = match_most;
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result = makeA_Expr(AND, NULL,
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makeA_Expr(OP, "~~", lexpr, rexpr),
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makeA_Expr(AND, NULL,
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makeA_Expr(OP, ">=", lexpr, (Node *)least),
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makeA_Expr(OP, "<=", lexpr, (Node *)most)));
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}
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}
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}
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if (result == NULL)
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result = makeA_Expr(OP, opname, lexpr, rexpr);
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return result;
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}
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/* xlateSqlType()
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* Convert alternate type names to internal Postgres types.
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* Do not convert "float", since that is handled elsewhere
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